Seventy-five years after the start of the blitz, second world war bomb sites continue to shape modern London, with second and even third waves of redevelopment throwing up buildings expected to last as little as three decades

I recently came across a photograph of a family eating a meal outside the broken shell of Sayer Street School, which was bombed during the blitz. It stood out, because Sayer Street no longer exists. This was once a long road of shops – a fishmonger, cat-meat dealer, grocer, saddler, bookbinder – and solid, five-storey tenements in Elephant & Castle. When the blitz began, the street was hit by several bombs.

What happened next to Sayer Street encapsulates several aspects of the waves of development that continue to shape London – and the central role played by the bomb sites of the blitz 75 years after the first explosions.

In the immediate aftermath of the war, Sayer Street was used as a car park. This was a popular use for bomb sites: indeed, the NCP car park empire began with the £200 purchase of a bomb site on Red Lion Square.

Then, in the 1960s, the remaining residents were turfed out as Sayer Street was demolished, chewed up by the Heygate Estate – a council housing development that was originally conceived as one of three gigantic estates stretching from Elephant to Peckham, linked by walkways and ramps for two miles. “These plans were incredibly radical, sweeping away neighbourhoods irrespective of damage and replacing them with high-rise towers nobody wanted to live in,” says Peter Larkham, professor of planning at Birmingham School of the Built Environment. The Heygate was bleak, poorly built and badly maintained, but it housed many of London’s poorest.

And then, last year, it was demolished, having lasted 37 meagre years. Southwark Council sold it to Lend Lease, a private developer that is building Elephant Park, a residential village of towers and plazas, where a three-bed apartment costs £2.5m. Those former residents who can’t afford flats in the new building – in other words, almost all of them – have essentially been displaced as efficiently as those who once lived on Sayer Street.

Concrete towers for the poor have been torn down and replaced with glass towers for the wealthy

Facebook Twitter Pinterest City of London skyline as seen from the Heygate Estate. Photograph: elephantpix/Alamy

Once you start looking around, it’s astonishing how often the bomb site of 1940 is the building site of 2015. Developers and planners are still working round decisions made when London was rebuilt following the aerial bombardment that began on 7 September 1940. More than 20,000 bombs fell on the city, destroying or damaging beyond repair 116,000 buildings.

“Everybody called it an opportunity,” says Larkham. “That’s a difficult word if you suffered from bombing, were made homeless and saw people killed, but it was an opportunity for many.”

You can see those opportunities marked out in colour in the Bomb Damage Maps, a series produced by the London County Council during the war showing colour-coded bomb damage across the city, building by building. The maps were originally created to help landowners deal with insurance and compensation, but were also used for postwar planning. They’re also fascinating for regular Londoners: they show, for example, exactly why there’s a council estate round the corner from my house in Herne Hill – the old Victorian terraces were obliterated by German bombs.

Facebook Twitter Pinterest A composite panorama of London after the blitz. Photograph: London Metropolitan Archives / City of London Police / London County Council Bomb Damage Maps 1939-1945 (Thames & Hudson)

If the bomb sites represented an opportunity, then it was a short-term one: the more I explored, the more I discovered that much postwar development has already been replaced. Concrete towers for the poor have been torn down and replaced with glass towers for the wealthy.

It’s a similar story with office blocks. A photograph in The Blitz: London Then & Now, John Neville’s book which juxtaposes photographs of bomb sites with the modern buildings that occupied the spot in 1990, shows The Ring on Blackfriars Bridge Road. The Ring was a Georgian chapel turned boxing venue, which was half-demolished in a bomb strike on 25 October 1940. But I didn’t recognise the building that replaced it. A stark concrete tower raised on a pedestal, this turned out to be Orbit House, an office block built in the 1960s by Richard Seifert, one of the UK’s most prolific postwar architects. The reason I didn’t recognise the building, I discovered later, is that it was itself demolished a few years after that 1990 photo was taken, to make way for Will Alsop’s Palestra, a square glass wall with overhanging roof. Whereas The Ring had over its 150-year life been adapted for several different uses – chapel, warehouse, boxing venue, theatre – Orbit House was demolished after just 30, unable to meet changing requirements and thrown away like a broken toy.

It’s astonishing how often the bomb site of 1940 is the building site of 2015

Facebook Twitter Pinterest On 29 December 1940, Cripplegate was razed in firestorms. St Giles’ church survived. Photograph: Daily Mail/Rex Shutterstock

A senior City planner told me that 30 years was about right for a modern office, as demands change so swiftly. Palestra – its name comes from the Greek word for a wrestling ring – currently towers above Blackfriars Bridge Road. It looks permanent, but if the planner is right, it will be gone by 2030.

“Some buildings have been demolished incredibly rapidly, before they’ve even been paid for,” says Larkham. “Can we afford to keep doing that? One of the worst products in terms of sustainability is concrete. The fact we can put these building up and then pull them back – is that really the best solution? We need to design for more flexible longer-term planning.”

This “second generation” blitz development has even taken place at one of London’s most successful postwar buildings. The Barbican was built over a scene of utter devastation: on 29 December 1940, the entire ward of Cripplegate was razed in firestorms. “Thousands of buildings have been burnt and blasted to the cellars,” wrote HV Morton in 1951. “Here and there the side of a building rises gauntly from the rubble, a detached gateway stands by itself in the undergrowth, the towers of a few churches, or a spire, lift themselves mournfully, like tombstones in a forgotten cemetery … How can anyone reconstruct a town from its cellars?”

Facebook Twitter Pinterest The Barbican surrounds St Giles’, Cripplegate. The initially controversial estate is now widely regarded as an example of successful postwar architecture. Photograph: Dan Sparham/Rex Shutterstock

Well, in 1965 construction began on the Barbican, which eradicated the old street plan, cellars and all. Completed in 1983, the initially controversial estate is now widely regarded as an example of postwar architectural ideals put into successful practice – but part of it has already been replaced. Milton Court, containing a fire station, mortuary and coroners court, was the first section of the Barbican to be completed in 1959, and in 2008 it was the first to disappear, replaced by new glass-walled facilities for the Guildhall School of Music and Drama, despite protests from conservationists who believed it should be saved.

Occasionally, these private projects disinter unexploded bombs that have sat silently under social housing blocks – a reminder of how quickly the second wave of redevelopment has come round and what it is replacing. One was recently uncovered on a building site in Bethnal Green, another on a building site in Grange Walk in Bermondsey last March, when two 1950s low-rise blocks were knocked down, displacing 54 households. The low-rises are being replaced by a large, mixed-used scheme of shops and 205 flats. If all the unexploded bombs went off simultaneously, one wonders if there would be any social housing left in London at all.

Occasionally, these projects disinter unexploded bombs that have sat silently under social housing blocks

Facebook Twitter Pinterest New facilities for the Guildhall School of Music and Drama replaced Milton Court – the first part of the Barbican to be built, and the first to be demolished, in 2008. Photograph: Alamy

A few sites at least are relatively undeveloped. The Caffe Nero branch on Tottenham Court sits in splendid isolation, all that remains after a V2 hit a church, killing nine people. The church was rebuilt but the rest of the plot remains empty. “There’s no absolute imperative that somewhere must be developed,” says Larkham. “Some property is owned by companies that don’t feel they have to develop, maybe nobody has come forward with a proposal or maybe it’s a SLOP [Space Left Over After Planning]. There were lots of these bits of lands that were purchased by agencies perhaps for road-widening schemes that never happened.”

Other sites were deliberately left derelict as memorials to the blitz, though even these have usually been touched by the busy hand of development. Christ Church on Newgate was destroyed by the December 1940 firestorm. While most churches were rebuilt, this was left as a ruin after The Times presciently wrote in 1944: “The time will come – much sooner than most of us to-day can visualise – when no trace of death from the air will be left in the streets of rebuilt London. At such a time the story of the blitz may begin to seem unreal not only to visiting tourists but to a new generation of Londoners. It is the purpose of war memorials to remind posterity of the reality of the sacrifices upon which its apparent security has been built. These church ruins, we suggest, would do this with realism and gravity.”

Facebook Twitter Pinterest Christ Church on Newgate Street was left as a ruin to remind Londoners of the horrors of the blitz – but is the site too polite to be effective? Photograph: Alamy

Christ Church barely fulfils this remit. Its remains have been laid out as a neatly landscaped garden, overshadowed by the large Merrill Lynch building. In 1974, two surviving walls were demolished in a road-widening scheme and in 1981, neo-Georgian offices were added in imitation of the 1760 vestry – these currently house a dentist. Even the church tower has been transformed into a 12-storey private home. The entire complex is a mess, but a very polite mess that evokes no great thoughts of human sacrifice; a campaign in 2013 to turn it into a more meaningful memorial was short-lived. But Christ Church at least fared better than another memorial-ruin: St Mary Aldermanbury was sold to Westminster College in Fulton, Missouri to act as a memorial to Winston Churchill. It can’t be long before City planners give up on Christ Church as a wasted opportunity, and stick a glass office in its place, maybe with a plaque.

The only thing stopping them from doing so is that in 1950 the ruins were given Grade I-listing, highlighting another legacy of the blitz: namely, the way the unforgiving nature of London’s postwar redevelopment spawned the modern conservation movement.

Columbia Market is a good example of how this process worked. On the first day of the blitz, a bomb hit a shelter in Bethnal Green, killing 38. Columbia Market, where it hit, was a Victorian development founded by Angela Burdett-Coutts, a philanthropist and friend of Charles Dickens. It was a combination of market and social housing constructed in a dramatic neo-Gothic style. Although the damage was repairable and the building was historically and architecturally significant, Columbia Market was demolished in 1960. It was replaced by a dismal modern tower block, named Old Market Square in a half-hearted nod to what was lost.

“The idea of heritage and listing buildings only really started after the war, when things were demolished so rapidly we don’t know exactly what was demolished and what was valuable,” says Larkham. “We now have 10,000 conservation areas and half a million listed buildings. Some planners think we conserve too much.”

In fact, the fate of Victorian buildings such as Columbia Market partly explains why postwar buildings are already being replaced – anything older has a conservation order slapped on it.

At any rate, conservationism arrived too late for Columbia Market, which now only survives as a section of railing outside a nursery. “It’s a fascinating building that must have cost a fortune and completely dominated the road,” says Laurence Ward of the London Metropolitan Archives, who has edited a 75th anniversary edition of the Bomb Damage Maps. “Now you’d never know it existed.”

This is a thought echoed by Alan Lee Williams. He was 10 when his home in Mayday Gardens, near Blackheath, was hit by a parachute mine. “It was meant for the Thames, but damaged 27 houses and took our roof off,” recalls Williams, now 84 and reflecting on a life that included a period as Labour MP for Hornchurch. Williams’s house was repaired. Several other houses – coloured black on the bomb maps, indicating “total destruction” – remained derelict throughout the war. Eventually the fire services built a water tank on the bomb site, which Williams and his twin brother would swim in.

The meticulously hand-coloured bomb damage maps of London – in pictures Read more

Visit Mayday Gardens now, however, and you’d have no idea anything had happened here, but for a surprising reason: the destroyed houses were rebuilt exactly as before. Some local residents I asked about the street’s history admitted it came as news to them. The careful reconstruction of these suburban homes comes as a stark contrast to the way working-class districts were treated.

Williams later lied about his age to join the fire service as a messenger, and was on Shooters Hill when a V2 rocket hit the Brook Hotel pub in November 1944, destroying a passing bus and killing 29. He was lowered into the rubble to rescue a survivor, a girl who lived on his street. “I still live in the area and I bow my head as I go past,” says Williams. “I always thought it was strange that there was never an explanation of what happened to these places. They should have put up plaques. It’s always a puzzle why it didn’t happen, maybe they just wanted to forget.” The pub was rebuilt before the end of the war. It currently houses a supermarket in an ugly makeshift building that has survived far longer than many more ambitious projects. Meanwhile, just a few miles away in the City and all along the Thames, the towers continue to rise above former bomb sites. London’s postwar reconstruction still isn’t complete. Will this version survive any longer than the last?

Follow Guardian Cities on Twitter and Facebook and join the discussion