Group London into streets and villages and it could densify well on many levels

Density by residential land area (excluding non-residential land)
Density by residential land area (excluding non-residential land)

Cities & Community winner

Jane Manning, George Garofalakis,
Antony Rifkin & Geoff Noble

London’s local character and density

Allies and Morrison LLP, UK

Set against a backdrop of a growing city – and one which is thirsty for sites needing intensification – Allies and Morrison was commissioned by Historic England to undertake a piece of research into London’s character and density. The work reveals a finer grain picture of urban character across London, moving beyond traditional – and simplistic – land use definitions to inform a more nuanced framework for planning and development. Amid major densification of the city driven by the absence of land for new homes, the research was a proactive contribution to the debates which shaped the new London Plan launched in November 2017.

The research reveals the need for a more context-led approach to intensification. Establishing a pan-London picture, it could allow character and heritage qualities to better inform all scales of planning in the city while also drawing together existing work and data. It is hoped it will also encourage finer grain characterisation work at borough scale, in particular studies that go beyond documenting existing character to inform the direction for future borough local plans.

Character and density

The study challenges a previous assumption that London has three broad character types: central, urban and suburban. Using geographic information software, a comprehensive mapping through London – taken as a transect from one end of the GLA boundary to the other – uncovered a rich tapestry of previously under-appreciated typologies, which have developed relatively independently of central, urban or suburban categories. In this, the report identifies finer grain character types that reflect a deep and variable history of London’s 1,000 year evolution. These types have been defined using a series of detailed information layers, including historic maps, historic and current land use, street structure, transport infrastructure, existing densities and heritage designations. This resulting map is set at a broad enough scale to be useful to strategic planning, but is supported by detailed information to allow more area-specific interrogation. These newly understood character types include designations such as Georgian planning and growth, Victorian suburbs, medieval market towns and high road edges – a much more sophisticated understanding of London’s places.

The more nuanced character typologies have evolved from a range of sources – from historic market towns to centres of Victorian industry. The new neighbourhoods have also been shaped by factors including transport links, ever shifting planning regulations and history. For each type, the prevailing characteristics are outlined including typical street widths, block dimensions, size of public spaces and density measurements.

Contributing to growth

The research has shown that all character types can absorb growth subject to a clear understanding of values and existing qualities. It is simply not true to say that historic areas cannot accommodate intensification. Indeed, many of the oldest parts of London have been the densest throughout history – and continue to accommodate new typologies and levels of intensity. A critical finding was that the greater the existing variety of character, the greater flexibility it held for future development.

Character areas which have seen many layers of development and infill – many of which are the most historic with a fine grain, have shown their ability to accommodate intensification and change. Where an area has a variety of characters evident, a greater range of typologies and density can be accommodated. Indeed, small fine grain plots can support surprisingly high densities and floor area ratios without recourse to large increases in scale. Equally, opportunities arise where post-war intervention, often with a coarser grain and less variation, has developed land in an inefficient way. The spaces in between in these areas are ripe for intensification.

The greater the existing variety of character, the greater flexibility it held for future development

It’s all about the streets

The study has demonstrated that street morphology is more important than anything, and that it is the streets that endure the waves of history. The principle of prioritising street structure is important. In each character area there are parameters which will steer or limit the level of intensification, but the single common denominator is street morphology and its role in shaping the relationship between street width and scale.

More rounded understanding

The study re-iterated other research and think pieces that a fundamental review is required into how density is measured, and parameters are set. We recommended that a review of the previous London Plan’s density matrix be undertaken, drawing on the findings of this research. It is important that future guidance on densities is nested within a robust policy framework which recognises the subtleties of density calculations and local character. A greater range of categories must be used to inform density measurements, and a more nuanced understanding of local character is essential in this.

Uniformity and change

An area’s uniformity can be a stumbling block to intensification. The suburbs are an important example where the homogeneity of an area makes it difficult to introduce new typologies or greater densities. Areas of uniformity are sensitive to changes in building height, as are historic villages which have been protected. Here, the ‘natural’ change that might have occurred has been steered elsewhere, leaving a character area more sensitive to such changes.

It is the streets that endure the waves of history. The principle of prioritising street structure is important

A resilient city

The grids of terraces and squares that characterise so much of the inner London boroughs have resulted in a diverse urban typology, accommodating a wide range of uses and activities operating at different scales and intensities. The inherently legible and permeable pattern of the block structure, with its public fronts and private backs, has supported the adaptation of buildings and spaces to a wide range of uses and subdivisions. The suburban development of the inter-war period has also proved an enduring model, albeit now much more car-dependent and therefore less able to support local shops and services.

The flexibility of much of London’s historic building stock will endure to support future changes. London’s position as one of the greenest global cities will also prove important in the face of climate change. The classic streets lined with plane trees provide a comfortable public realm capable of adapting to more extreme weather. These trees will provide shelter and shade, both to the pavements and squares, but also to the buildings they grow next to. They are an important means of carbon sequestration.

When similar administrative areas are compared, London shows itself to be the greenest of global cities – with over a third of land area as green space. While the private gardens of suburbia contribute significantly, it is the public parks and public open spaces which make the greatest contribution to character. Indeed, it is interesting that there are more parks and public open spaces by land area in central London than there are in inner London and more here than in outer London. Strong public parks and green spaces are integral to London’s being.

Looking across all the character areas it is the prevailing floor area ratio ranges that give the strongest indication of how sensitive an area is to intensification. Where the range is small, the scope for appropriate intensification may be more limited to sub-division, small scale extensions and infill schemes.

These findings could assist in better use of heritage assets in the future, alongside a more sophisticated understanding of street morphology and urban grain and how these can accommodate change. By embracing the true diversity of London’s character typologies, this work provides a contextually-rich reframing of the way London could plan for intensification.