What a Hiroshima-sized blast would have done to LONDON: Unseen government diagrams imagine carnage if nuke was used on UK in 1945
Imagine a very different end to the Second World War.
Instead of the US dropping the world’s first atomic bombs on Japan, it was the Japanese hammering London with the devastating new weapon.
In 1945, that is more or less what was considered by the British government, which was freshly in the hands of Labour’s Clement Attlee after his triumph over Winston Churchill at that year’s election.
Official diagrams envisaged the impact of atomic bomb blasts in London, with the force described as being equivalent to what was unleashed on the cities of Hiroshima and Nagasaki on August 6 and August 9, 1945.
One of the two maps – recently seen by the Mail at the National Archives in Kew, West London – imagines the impact of a bomb detonated over Trafalgar Square.
It said everything within 1,000 yards of the epicentre – so all of Whitehall, Covent Garden and St James’ Palace – would be totally wiped out.
Then, there would have been damage ‘beyond repair’ to areas within a distance of one mile – including the rest of Westminster, Buckingham Palace, the BBC‘s headquarters and the British Museum.
The likes of St Paul’s Cathedral, Smithfield Market, Victoria Station and Marble Arch were within the third ring up to 1.5 miles away, described as ‘uninhabitable without major repairs’.
The mushroom cloud caused by the bombing of Hiroshima on August 6, 1945
The final ring – up to 2.5 miles away – includes King’s Cross Station, the Bank of England, Tower Bridge, Battersea Power Station and Regent’s Park.
Everything in this area would have been ‘uninhabitable without first aid repairs’, the report’s authors said.
The two maps feature as part of a file that also includes a report titled, ‘An Investigation of the Effects of the Atomic Bombs Dropped at Hiroshima and Nagasaki’, which was compiled after an official visit to the ruined cities by British officials.
The other map gives a wider view, showing the impact of five blasts over London. Again the explosions are ‘as at Hiroshima and Nagasaki’.
As well as the bomb over Trafalgar Square, four others are depicted detonating over Poplar in East London; in Primrose Hill above Regent’s Park; in Hammersmith in West London and in Tooting in South London.
Collectively, they would have rendered nearly all of Central London a flattened wasteland.
Areas such as Lambeth in the south of the capital would have been unscathed, but the borough’s inhabitants would have faced having to grapple with a likely total breakdown in law and order and a collapse of the emergency services.
Although the official report – which was compiled by the British Mission to Japan – is dated December 1945, the maps themselves were made the following year, as an Ordnance Survey label on them shows.
One of the two maps seen by the Mail at the National Archives in Kew. It imagined the impact of an atomic bomb attack on London. It is dated 1946
The key on the map detailing how everything up to a distance of 1,000 yards from the epicentre of the blast would have been ‘demolished’
The foreword to the report optimistically concluded: ‘His Majesty’s Government consider that a full understanding of the consequences of the new form of attack may assist the United Nations Organisation in its task of securing the control of atomic energy for the common good and in abolishing the use of weapons of mass destruction.’
The British mission included scientists and senior officials in the Home Office, War Office and Air Ministry.
It laid out in horrifying detail the devastation wrought by ‘Little Boy’ and ‘Fat Man’ – the atom bombs dropped on Hiroshima and Nagasaki by US forces.
In Hiroshima, the blast – at 8.15am on August 6, 1945 – obliterated everything within the surrounding square mile, killing around 80,000 people in the blink of an eye.
At least 30,000 more died from their devastating injuries in the 48 hours that followed.
A total of five square miles of the city were consumed by fire storms, and the blast obliterated 90 per cent of Hiroshima’s structures.
The police, fire and ambulance services were all virtually wiped out, with survivors left to fend for themselves before help arrived from further afield.
The attack on Nagasaki came on August 9, after Japan refused to surrender despite the carnage in Hiroshima.
The file in which the maps were tucked away, at the National Archives in Kew, West London. British officials compiled a report titled, ‘An Investigation of the Effects of the Atomic Bombs Dropped at Hiroshima and Nagasaki’
The second map found at the National Archives, imagining five separate atomic bomb blasts in London
The key for the second map, explaining the colours detailing the respective levels of destruction
The device – Fat Man – was carried by the B-29 bomber named Bockscar. It claimed at least 50,000 more lives and wiped out a third of the city.
Japan finally agreed to the Allies’ terms of surrender on August 14.
The British Mission’s report estimated that, for several reasons, the impact of a blast like the ones that hit Hiroshima and Nagasaki would be less devastating in London.
Because of factors such as population density, the presence of well-built houses offering more protection and better rescue services than in Japan, the death toll from a single blast is estimated at 50,000.
But the report chillingly added: ‘The comparable figure for the German V2 rocket was about 15 dead’.
The authors continued: ‘The figure of 50,000 dead from one atomic bomb in average British urban conditions is probably the most important which this report contains.
‘It shows that much of the most serious effect of the atomic bomb is in producing casualties.
‘The problem of providing against and of treating gamma ray casualties is exceptionally grave and difficult.’
Survivors of the US attack on Hiroshima sit in a makeshift hospital that was set up in a bank building in the ruined city
The explosion of a bomb of the power of those used in Hiroshima and Nagasaki would have wiped out around 30,000 houses in a British city.
Between 50,000 and 100,000 more properties would be rendered temporarily uninhabitable.
The report went on: ‘Thus a total of roughly 400,000 people might be rendered temporarily homeless’.
It was not until the 1970s – when the risk of conflict with the Soviet Union was high – that the Government’s public information campaign advising what to do in the event of a nuclear attack was released.
The ‘Protect and Survive’ series told Britons to prepare a ‘fall-out room’ in which they would need to store enough food and water for two weeks.
They were also advised to bring the likes of kitchen utensils, a portable radio, toilet paper, a bucket and a first aid kit.
Shortly after the leaflet was released, expert critics said the advice would not be helpful.
One said the protective measures were ‘illusory’ because people would immediately ‘panic’ in the event of a nuclear attack.
The bomb was detonated at around 1,890 feet above the city. Everything within an immediate square mile was obliterated
The Protect and Survive campaign also included newspaper adverts, radio broadcasts and public information films.
Whilst the campaign had been intended for use only in an emergency, it came to public attention in a series of newspaper articles.
The Government then decided to publish the leaflet in May 1980 and the public information films were leaked to the BBC and anti-nuclear group CND.
The 1984 BBC drama Threads depicted the horrifying consequences of a nuclear attack on Britain.
Threads was watched by seven million people on BBC Two and won four Baftas, but it also left many viewers traumatised.
The gruesome details – the shocking burns, the radiation sickness, the obliteration of buildings following the imagined attack on the city of Sheffield – were a constant presence in the drama.
Dozens of those who watched were so shaken that they called the charity Samaritans for support.
