London's main roads can accommodate growth and make our city more like itself

London's population, according to the Office for National Statistics, is projected to grow by 13% - over a million people - between 2012 and 2022.  This means there is a need for more of every type of building - offices, factories, schools and hospitals - as well as the homes that are the main subject of discussion when growth is discussed.

There is plenty of room within Greater London to accommodate this growth, and that is what the London Plan proposes to do.  But it's not easy to reconcile this pressing need with the tendency of local authority planning committees to resist it in their decision making.  It seems unlikely that if asked, committee members would support people being accommodated in sheds in the back gardens of TfL's zones 4 to 6, but that is what happens at present - out of sight, out of mind, perhaps.

London is not like New York (hellzapoppin, at least in Manhattan) or Paris (homogeneous, at least until you get out to the banlieues).  Its growth projections are twice those of New York, but it needs to find its own way to expand, not become like somewhere else.  Development areas such as Nine Elms are criticised, with some justification, as appearing to have little to do with the character of London; and even Canary Wharf, accepted by most Londoners for what it is, has little obvious connection with the rest of the city.

One way that London could grow in a more London-like way would be to concentrate incremental growth - extensions and new buildings - along main roads, both in the centre and elsewhere.

Typically, London's main roads are larger in scale, and more varied and changeable than the side streets the run off them.  They were often developed before the side streets, but have been redeveloped more frequently, so there is less that is precious, and less that is homogeneous.   Outside the centre of London, and in places in the centre too, main roads also tend to be more run down and in need of visual improvement.  Camden High Street and Hackney Road are typical examples - visually grotty environments with smart side streets only yards away.

Main roads can accommodate change, variety and increased scale more readily than side streets.  In order to accommodate growth, there should be a presumption in favour of enlarging existing buildings on main roads, or replacing them with large new buildings.  Such a policy should explicitly recognise that these large new buildings will be seen from neighbouring conservation areas and in the backdrop of listed buildings and that this is not inherently harmful.  It is already characteristic of London.   When done well, such contrasts improve the city and do not to harm it.

The upward extension of a building on Euston Road that is illustrated above is an example of what can be done.  Sensibly scaled and neatly executed, doing what is appropriate and no more, it enhances the base building below and is readily accommodated in the varied existing streetscape.  Notably, it shows that it is not compulsory for upwards extensions to be 'roof-like', mimicking mansards from the days before we had lifts, when the top floors contained the least desirable accommodation, not the most desirable as they do now.

Paris is largely homogeneous in the height of its buildings.  New York is the opposite, but its gridded urban block structure is very unlike that of London - all roads have equal, democratic, weight in the urban hierarchy.  A strategy of intensifying built form along the main roads would be in tune with the character of the London that already exists and would have the effect of making London more like itself rather than like somewhere else, such as the Dubai-on-Thames complained of by the moaners.

It could also have the effect of bringing about much needed visual improvement to some of London's most visible signs of the persistence of urban decay in some theoretically desirable parts of the capital, while massive, but not necessarily appropriate, redevelopment takes place elsewhere.