A very wide range of organisations and individuals, own and manage lighting, and the expertise and resources they allocate to it vary greatly. For this reason, there are a number of different plans, permissions and processes that regulate lighting in London, depending on the type of lighting in question. This section maps out the broad processes followed, from design through to management, and discusses the challenges that face those responsible for lighting the city.
Lighting is a public service which local authorities provide and manage, generally as streetlights. From its predecessors centuries ago, the illumination of roads and streets has always been focused on allowing safe passage along a route. However, the dominant method of travel has changed over time, and with it the way lighting is designed.
Lighting for cars
The mass adoption of the car in the 20th century dramatically changed the way we live in and move through cities, as well as how we build and design them. The vast majority of public lighting today is testament to this. Even in older areas built before the car, the prioritisation of road space for vehicles has meant in practice that lighting is designed for them. Since the establishment of the modern boroughs, local authorities in London have been responsible for the majority of both public lighting and highways upkeep. On the Transport for London Road Network, TfL are responsible for street lighting and highways maintenance.
The very first British Standards for street lighting 41 and central government regulations were developed explicitly to facilitate the safe and smooth flow of traffic. 42 Almost a century later, the principles remain the same. The majority of our street lighting is intended to light the carriageway first, with footway and pedestrians second. This is the “classic” light mounted high up on a pole, close to the kerb and overlooking the road. The majority of industry standards and guidelines accord each type of road a category, which is essentially based on how heavy its traffic is. In this sense, design largely follows a functional, prescriptive template – roads are lit to defined levels of light in order to allow visibility for drivers. As such, the potential variables are limited.
New generation of infrastructure
The biggest changes in recent years have come in the widespread adoption of LED technology. LED lights are more energy-efficient: projected energy savings from switching to LEDs are between 50 and 80 per cent, and they have a much longer life cycle than traditional lamps. It has been estimated that lighting comprises up to 30 per cent of an average local authority’s total energy bill.
The other advantage of LEDs is that they allow for a greater variance of colour and brightness. When paired with a remote Central Management System (CMS), individual fixtures or groups of them can be changed across the evening, in real time. This means that street lighting can be designed to respond more appropriately to the range of different users and needs within a public space – and with the quality of light in mind.
LEDs also allow for better targeting of light, losing less in upwards light pollution. The image below of Milan, before and after wholesale upgrading to LEDs, shows the impact this can have on a citywide scale.
Where is London in the roll-out of new technologies? In researching this report, we audited all large-scale lighting interventions carried out by local authorities since 2010. We found that all London local authorities had either begun or completed upgrading their older sodium and metal halide lighting to LED lamps, starting in 2011 (two years after LED streetlights were first installed in the UK). Similarly, Transport for London has carried out large-scale replacement of the lighting assets across their road network.
This investment has largely been driven by energy saving concerns, but few London authorities have used this opportunity to take a more strategic approach to their lighting – to consider what type of light is needed, where and at what time of the night. This infrastructure will now be in place for at least 15 years, so we will need to wait until the next round of upgrades to see improvements to most public lighting across London.
One authority that is showing the full potential of what the next generation of public lighting can do is the City of London Corporation (see case study overleaf).
Case study: The City of London Corporation’s lighting strategy
The City of London Corporation’s lighting strategy goes far beyond simple lighting of the highway for drivers. Making full use of the potential of LEDs and central management technology, the strategy shows how modern urban lighting can be designed to reduce light pollution, enhance the pedestrian experience, improve the public realm, maintain feelings of safety, and enhance accessibility. The implementation of the lighting strategy has enabled a 20 per cent reduction in the number of light fittings and a 50 per cent cut in energy consumption.
The strategy divides the Square Mile into particular “character” areas, with context-specific lighting for the different functions, users and atmospheres of each place. Maximising the particular attributes of each area is an explicit aim of light as a placemaking tool. Light is positioned to help people navigate the streets on foot, with particular attention to the needs of users with reduced mobility. This is done by reducing glare and contrast, and integrating as far as possible with the existing urban fabric. Care is taken to explicitly reduce all types of light pollution by considering reflective surfaces, existing light levels, and avoiding direct sky illumination. Lighting levels respond to how busy a street is at different times throughout the night. The CMS also allows for brighter lighting on demand, for example if needed by emergency services.
The strategy provides direct guidance for the design and management of public lighting, and outlines principles to be adopted for planning documents in order to guide the use of private lighting within the City.
However, the City of London Corporation has a vastly different funding arrangement to the rest of local government in England. Pressures on local authority budgets in recent years have impacted the departments responsible for lighting. The chair of the London Lighting Engineers Group – an organisation which convenes the lighting professionals working across the London boroughs – explained that London local authorities receive less funding than is needed to maintain their lighting infrastructure, let alone invest in new material.
Boroughs usually receive funding from TfL via the Local Implementation Plan (LIP) process – under which boroughs demonstrate how they will meet the objectives of the Mayor’s Transport Strategy. However, at time of writing, the LIP process is paused. The huge drop in fare income as a result of changes in mobility due to the COVID-19 pandemic has made TfL reliant on central government funding to continue operations. In the future, alternative sources of funding may be needed to adequately resource lighting in boroughs, such as income generated from development receipts.
The resource pressures faced by local authorities in managing public lighting are not only limited to hard assets. In many authorities there are only one or two experienced lighting engineers, and some have no internal expertise at all. These specialists have a broad remit: beyond core maintenance and upgrading, they may have to respond to issues as stakeholders were around the table and party to discussions from the outset. Without the expertise of a lighting designer, engineers or architects may refer to guidance documents for assistance. This can bring its own problems. Even guidance documents which are considered to represent good practice in design can fall short when it comes to lighting. The Manual for Streets – wide as incorporating 5G transmitters, electric vehicle charging points, CCTV cameras, weather monitoring sensors, and other technologies. These considerable workloads fall on relatively few staff, who have limited capacity to act in a strategic role and advise on wider changes to how lighting operates – though some of these operations could generate income for lighting infrastructure or reduce maintenance costs.
Input and expertise
The administrative arrangements of councils can also prevent lighting from being taken as seriously as it deserves. Our review of borough lighting interventions shows that 60 per cent of street lighting upgrade programmes were the responsibility of Highways departments, while 15 per cent were the responsibility of what could be grouped together as “Environmental” departments, covering areas with broader remits for neighbourhood management.
Properly integrating transport-related functions with strategic planning is an issue that extends beyond lighting, but applies here too. It is crucial to ensure that lighting is considered alongside other disciplines at an early stage as a core component of good placemaking. Where boroughs have carried out particularly good lighting schemes, there is often a much less siloed approach. For example, the delivery of lighting schemes in Southwark included collaboration with officers responsible for regeneration and urban design, as well as community groups, BIDs and social researchers. 43 When the City of London was developing its strategy, it convened a Lighting Board to ensure that the relevant stakeholders were around the table and party to discussions from the outset.
Without the expertise of a lighting designer, engineers or architects may refer to guidance documents for assistance. This can bring its own problems. Even guidance documents which are considered to represent good practice in design can fall short when it comes to lighting. The Manual for Streets – which does at least discuss the aesthetic qualities of lighting 44 – was published in 2007, and as such does not consider the adoption of LEDs, which has profoundly changed the potential for street lighting to be used more subtly and creatively.
Another challenge can be found in the way that public lighting is sometimes procured. Across a number of local authorities in London, street lighting is delivered through Private Finance Initiatives. One single company will provide the complete service over a long period, from inception through to maintenance. Depending on contract design, this model may create an incentive throughout to keep the costs down, with good design losing out as it is not considered a priority. Being mindful of the incentives that procurement choices can create will help mitigate such risks.
Private lighting and regulatory frameworks
While municipal lighting might be the most recognisable form of artificial light in the city, it may not be the main source of light by every measure. As public bodies grapple with how to improve lighting within their direct control, a large amount of light in the city is emitted from private sources. Illuminated shop signs, window displays, advertising, interior office lighting, residential security lights, hazard lights on construction hoardings, spotlighting of buildings, stadium lighting and even cars all contribute to direct and indirect illumination of our streets and common spaces – as well as total skyglow and ambient light pollution.
There is currently no estimate of how much private sources of lighting contribute to overall light levels in London or in most cities – which in itself shows we have paid little attention to it. The most comprehensive study, conducted in Tucson, Arizona, examined the contributions of new LED streetlights to total ambient radiance visible from space. It found that streetlights in Tucson contributed between 13 and 18 per cent of total light visible from a satellite, 45 depending on dimming. Of course, this is merely one way of measuring light pollution, and in many cases direct illumination can be more harmful, but the findings are nonetheless striking.
Closer to home, a study of light sources in Paris found that private sources represent more than half the light shone towards the sky – and therefore a large contribution to “skyglow”. While London is a different city, this finding is a powerful indication that measures to tackle over-illumination should take private lighting far more seriously.
Some consider the lighting of shopfronts or offices when not in use as excessive – creating visual clutter on top of being a waste of energy. 46 The rapid growth in the number of skyscrapers with significant amounts of glazing is also making an increasing contribution to total lighting levels, without consideration to external impacts. Luminance surveys on the banks of the Thames show how office buildings have come to dominate central London’s nightscape, not just in the late afternoon but throughout the night.
Others see private lighting as an opportunity, adding character and interest to streets that would otherwise only bear the mark of our rather controlled and linear approach to public lighting. London is hardly a cohesive place in design terms by day, and private lights contribute to its “big city” feel by night. We could harness private lighting to a greater degree: sensor technology now even allows public lighting to be dimmed where private sources provide enough illumination in the right place. 47 As we have seen, private lighting comes in many forms: some large luminous advertisements are often seen as detracting from the character of a place rather than adding to it, although there is a notable exception in Piccadilly Circus. There should be a debate on how permissive London should be in terms of lighting, given the positive impacts of well-considered lighting and the negatives of poorer uses.
The design of private lighting can be controlled in part through the planning system. As a principle, light itself does not require planning permission. 48 Whether or not external light fittings require planning permission varies according to the intensity, positioning, scale, significance, and surroundings of the lighting (and typically, the development of which it forms a part). Stand-alone lighting interventions often do not require planning permission, although some (such as illuminated advertisements) do. Generally, local authorities can shape private lighting at the point of approving development.
As such, one way for planning authorities to shape private lighting would be to create strategic policies on artificial light as part of their local development frameworks. But these are currently lacking. At the national level, the National Planning Policy Framework says little about lighting, talking only in broad terms about the need to avoid light pollution. At the city level, the London Plan does not dedicate a great amount of space to lighting though its Policy D8 on Public Realm requires new developments to reduce light pollution and design public spaces that encourage social interactions after dark. Being a strategic document, the London Plan is not intended to provide the level of detail necessary for practitioners to use in designing a scheme. Nevertheless, lighting is less of a concern than other issues. A word search for “lighting” in the London Plan gives 15 results, whereas “noise” gives 126. In the Mayor’s Environment Strategy, light pollution is mentioned once as something which can be mitigated by land use policy. In contrast, “ambient noise” has an entire chapter dedicated to it.
London is falling behind other cities in this regard. Glasgow has had an adopted lighting strategy since 2002, Paris has had a citywide lighting strategy since 2000 and Seoul since 2005. Since 2010, smaller European cities like Eindhoven, Copenhagen and Gothenburg have all developed lighting strategies and masterplans. For a pre-eminent global city, London is off the pace. The lack of serious consideration at a strategic citywide planning level is mirrored at the borough level. The City of London’s lighting strategy, adopted in 2019, was the first in London.
Without strategic oversight of lighting design feeding into local guidelines, the results at development control stage can be haphazard. For example, in an interview with an experienced lighting and environmental consultant, we were told that the detail required in an external lighting statement for a development differs dramatically across planning authorities. Some planners may want detailed information about light spill; others will defer to industry guidelines and standards, which can be a blunt instrument when not used by specialists.
Accepted professional guidance provides some frameworks for avoiding over-illumination and obtrusive lighting. 49 These are only intended to be a broad outline, as the levels of site-specific detail required to design good-quality lighting cannot be generalised. These are based around suggested illuminance levels for different types of environments called “Environmental Zones”. Across a city setting, these range from “Rural” (“relatively dark outer suburban settings”) through to “Urban” (“town/city centres with high levels of night-time activity”). 50 The guidance recommends explicitly that a competent lighting designer be engaged when considering any exterior lighting. However, local authority planning officers, who are as overstretched as lighting engineers, may not have the option to consult a specialist.
For heritage buildings, Historic England offers guidelines to help owners of listed buildings design a good lighting scheme that makes the most of landmarks at night. 51 Historic England’s development advice team also provides advice on lighting strategies and proposals to light Grade I and II* buildings.
A substantial amount of artificial lighting in the city is also provided in situations where there is no design process and no planning framework. This is the case for the illumination of most shopfronts or offices.
Local authorities and the Environment Agency do have powers to deal with excessive light if it is classified as “prejudicial to health or a nuisance”. However, these are only powers to tackle individual issues: they cannot provide the strategic oversight that a whole-city approach needs. Where London lacks a coordinating set of principles to manage the operation of its lighting, the responsibility falls on individual actors. This can work for estates in single landownership, so wholesale redevelopment treated well could result in a coherent night-time landscape. But in areas of more diverse ownership and responsibility, like a high street or town centre, the result is hit-and-miss.
The importance of professional expertise
The lack of attention given to lighting in design does not only happen through the planning system. Another issue mentioned by several interviewees was that lighting designers are commonly overlooked as an integral part of a multidisciplinary design team – and on the occasions that they are engaged, it is frequently later in the process. This means that lighting designers’ ability to meaningfully impact a scheme can be limited. One lighting designer who works internationally contrasted her experience in the UK with working in the Middle East:
“Over there, lighting designers are at the table right from the beginning of the project. If you want to integrate lighting into the urban furniture, you have to be able to shape it from the beginning. If you come late, you miss opportunities to reduce clutter, integrate servicing and consider things holistically.”
Of course, there are good developers and schemes where lighting is taken seriously. These tend to involve the kind of early engagement with specialists and careful evidence gathering that will create a good result. However, these are typically projects of a particular profile and scale, often involving heritage buildings and important architecture. As well as their architectural and artistic merit, these schemes can also demonstrate the importance of good lighting, and serve as an entry point for wider conversations about improving lighting practice across the city.
These schemes, however, are not the norm. The consultant responsible for the Thames luminance study described above told us that only projects of a certain value would justify the expense needed for this kind of evidence. Even for many sensitive historic buildings, architectural lighting can be poor. A specialist heritage building consultant told us that manufacturers of lighting fixtures are often acting as designers and selling their products as an off-the-shelf “solution”. The limited number of heritage specialists who can advise or intervene on lighting means that often, buildings of particular interest and importance end up poorly lit – and Londoners miss out on what should be beautiful additions to the city at night.
Detailed design issues
On residential streets with lighter traffic – away from town centres and where cars should be a lower priority – other aspects of lighting could in theory be foregrounded. However, good lighting design usually struggles to get a look in. One experienced lighting designer told us that in practice this rarely happens, and non-specialists are left to make the decisions.
Other aspects of our urban design and built fabric can pose a challenge for good lighting in and of themselves. Dense apartment blocks that face onto a common area can be at higher risk of light intrusion into flats, which can be a nuisance for residents. Specific design features of some building typologies can also create challenges. Deck access blocks pose a particular problem. One interviewee, an experienced lighting designer with a focus on housing estates, told us that these are commonly over-lit, in part due to housing officers deferring to inappropriate standards:
“The standards don’t recognise that these “corridors” are external, and outside people’s windows. One resident on an estate I was working on had to black out her window with cardboard as the glare was so strong it was keeping her awake at night!”
Hard-wearing fixtures, designed for resilience due to a perceived danger of vandalism, also diminish the ability to tailor the angle of lighting and fit shields to prevent this kind of light pollution.
Special attention needs to be paid to facilitate navigation where buildings do not follow a traditional street pattern. Having lamps positioned so that pedestrians can “read” the space, as described above, is especially necessary where there is divergence from the classic layout of a continuous line of houses fronting onto a street. Similarly, designing an appropriate lighting scheme for a pedestrianised space with both a place and movement function requires a proper understanding of its specific dynamics. According to the same interviewee, this also rarely happens:
“The problem is that this kind of data is not easily quantifiable – having qualitative analysis doesn’t tick the council’s boxes of consultation. They want numbers they can say agreed to a yes or no question.”
Again, proper evidence gathering and genuine local engagement are necessary to design a well-functioning lighting scheme. As public bodies move from upgrading the bulk of their lighting infrastructure on highways, they should consider their remaining lighting infrastructure on estates as an opportunity to improve their practice.
Case study: Illuminated River
Illuminated River is a landmark public art installation across the river Thames. The installation involves lighting up nine major bridges across a two-mile stretch of the river over the course of two years. Inspired by the life of the river and the communities alongside it, the project demonstrates how light can transform some of our cities’ greatest assets – in London’s case, the river. By referencing the shades of light across both day and night on the river, as well as the ebb and flow of the river itself, the lighting works with elements already present to create a new, beautiful way of experiencing one of the city’s most important public spaces. 52
However, the project is not only groundbreaking in its design. Sensitively integrating new lighting into an already heavily lit urban context means paying close attention to existing conditions. A luminance study was carried out along the length of the site – an unprecedented scale for such a study and the first to be done along the Thames. It measured light levels along the bridges to be included in the project, as well as the banks. Beyond demonstrating the extent of light pollution from the bridges themselves – which the new lighting will reduce by 75 per cent – it also showed that a significant amount of light pollution came from streetlights and over-lit buildings. The impact on wildlife, in what is a sensitive habitat for marine life, bats and birds, was thoroughly researched in partnership with conservation organisations. The changes to the design as a result will mean new lighting that creates a better environment for wildlife.
Case Study: Shadwell Estate
Shadwell Estate is a Peabody estate in Tower Hamlets that demonstrates the difference good lighting can make in housing estates, as well as the value of public engagement. As part of a programme by the landlord to improve the public realm across their estates, the new lighting of Shadwell Estate focuses on giving its residents a better outdoor experience while also complementing landscaping improvements.
The project was carried out following resident engagement. Through one-to-one interviews, observations, focus groups, group events, and presentation of sketches and ideas in conjunction with the landscape architect, the desires and needs of residents shaped the final design. This included fitting lighting suspended on wires to retain the maximum amount of usable floorspace.
The estate, which was previously illuminated using floodlights, has undergone a complete transformation. Accent lighting to the main entrances, lighting integrated into wayfinding signage, and uplighting on trees have all helped to create a welcoming environment and introduced a new sense of pride among residents and visitors.
“The light is great, now the children can play outside in the evening.”
“Everything looks so good. We’re coming here now, because we prefer it to our house!”