This triangle of charitable housing was built in 1913 to accommodate small families and women on low incomes. It sits on the sort of prime site that any developer would love to demolish and build on. But it has been saved from the wrecking ball.

A tireless campaign by the Victorian Society, which fights for the preservation of endangered buildings, with support from comedian Eddie Izzard, has blocked the landlord’s plans to flatten the blocks to build luxury apartments.

The 674-home site is considered of human and architectural significance and the issue here is not just about the provision of much-needed homes but the documentation of the city’s past, says Jane Kennedy, architect at heritage consultants Purcell.

“Heritage buildings embody and communicate our history,” she stresses.

Retroffiting comes with environmental benefits

Air pollution costs the London economy £3.7 billion a year and a quarter of the capital’s primary schools are in neighbourhoods that breach the legal limit for poisonous nitrogen oxide. Old cars get the blame.

However, construction is a major contributor to this public heath crisis. Responsible building means limiting demolition - and therefore dust - where possible, reducing the need for concrete and using less energy.

“There is real urgency for those of us in the property world to think about every possible thing we can do to reduce carbon emissions much faster than the Government’s commitment to hit net zero by 2050,” says Basil Demeroutis, of property investment firm FORE Partnership.

“One way of doing that is to work with existing structures. It’s crazy we are knocking down buildings that are only 30 years old. Retrofit all buildings - not just those that may be valued for heritage reasons.”

Where are the most listed buildings in London?

Listed buildings and traditional architecture are associated with the most expensive parts of London.

New research from Savills reveals that Kensington and Chelsea has the highest proportion of pre-1900 homes of any London borough, at 64 per cent. The average house price is

It’s followed by Hammersmith and Fulham (53 per cent), Camden (48 per cent), Westminster (46 per cent) and Lambeth (39 per cent). Just one per cent of stock in Barking and Dagenham pre-dates the 20th century.

The history and appearance of a property becomes part of the sell and, in the luxury homes market, bumps up the price.

“New planning laws in Westminster [due to come into force in January] ban the knock-through of multiple homes into anything bigger than a five-bedroom residence. Basements have also been outlawed.

"This means the large traditional mansions will be considered very rare, driving up the price in central London,” explains Becky Fatemi of Rokstone Properties.

“Our Chinese buyers, in particular, love a traditional exterior with a brand new home inside,” she adds.

That sums up 20 Grosvenor Square. Residents are now moving into the former US naval headquarters and wartime home of General Eisenhower.

The original Georgian façade was held up by steel scaffolding while the mansion behind was demolished and rebuilt into 37 opulent apartments serviced by the Four Seasons hotel group.

Prices start at an eye-watering £17.5 million for a four-bedroom home.

Heritage homes at accessible price points

There are heritage homes across the capital at much more accessible price points. Kingston Head Post Office is a Gothic building that dates back to 1875 and sits next to a 1908 Arts and Crafts-style telephone exchange.

Both Grade II-listed buildings are in a state of disrepair but will become the cornerstone of St George’s latest scheme, The Royal Exchange, designed by Malcolm Fryer Architects.

On the ground floors will be restaurants and cafés set around a public square and upstairs will be dedicated to the community.

The development launches on Friday with plans for 320 homes in new surrounding buildings, a gym, cinema and 24-hour concierge service. Prices start from £480,000. For more information, call 020 3740 4702.

Your own 'Downton Abbey' in Enfield

In Enfield, north London, Berkeley Homes is restoring Trent Park mansion, once home to famed socialite, arts patron and Conservative politician Sir Philip Sassoon (1888-1939).

The 56-acre grounds date back to the 14th century but Trent Park mansion was rebuilt in 1923. Fourteen new homes in the Grade II-listed building will have cornicing, coving, panelling and ornate fireplaces.

Windows that were bricked up have been reopened so that residents can enjoy the original views over the lake. Antique chinoiserie wallpaper has been gently stripped and restored off-site to be put back up.

Once finished the whole scheme will house 250 homes with prices starting from £575,000. Visit trent-park.co.uk or call 020 3005 5590 for more details.

The latest phase - the Wisteria Collection - has just gone on sale. The four-bedroom semi-detached homes are on Rightmove for £1,405,000.

Heritage buildings are a window into our past, but the environmental benefits of repurposing them into new homes will also help preserve the future.

Art Deco conversion in Crouch End

Nine apartments and mews homes have been carved out of a 19th-century printing plant turned-newsroom in Crouch End.

The Twenties Art Deco façade of The Printworks, once the office of the Hornsey Journal, has been retained along with exposed steel beams inside by the Unique Property Group.

“We have a contemporary, open-plan flat set within a gorgeous building with nods to the past. The front is eye-catching but still fits into the architectural landscape of the neighbourhood,” says new resident David Bromfield.

David and his wife Amber get free car club use for three years. Prices of the remaining mews houses start from £1.1 million. Call Castles on 020 8348 5515.

Converted mill for commuters

On the Thames in Berkshire is Taplow Riverside, a Berkeley Homes development based around a Grade II-listed paper mill which operated from 1767 to 2006.

International businesswoman Lara Auger and her 21-year-old daughter Selina have bought a two-bedroom flat at the scheme.

“The design of the homes was a big factor in my move to Taplow. I love the craftsmanship of the property and attention to original details,” says Lara.

Prices range from £475,000 for a one-bedroom apartment to £1,675,000 for a five-bedroom detached home.