The worst civilian tragedy of World War II in Britain occurred on September 10th 1940 when a German bomb landed on a school London's East End killing 600 people.

The men, women and children had been sheltering for three days in the school's basement waiting to be evacuated to escape the bombing.

For 70 years we have been led to believe that the death toll in the tragedy of Hallsville Junior School in Canning Town was 77.

But newly-unearthed papers in the National Archives reveal the TRUE horror of September 10, 1940. The papers reveal that the true death toll of 600 was hushed up to preserve morale, and that Home Secretary Sir James Anderson did not tell even Churchill about the true extent of the carnage.

Now, 70 years later, the sole survivor can finally pay her respects to the mum and baby sister she lost.

Blitz bomb killed 600 in school, details kept secret for 70 years

EXCLUSIVE by Susie Boniface
The Sunday Mirror

In September 1940 a German bomb fell on a school killing 600 civilians sheltering in its basement. The full extent of the tragedy was hushed up to preserve morale. But after 70 years the sole survivor can finally pay her respects to the mum and baby sister she lost.

Survivor: Pat Wardle was just 8 years old

It was Britain’s worst civilian tragedy of the Second World War – 600 people buried alive in the East End of London.

But for 70 years what happened at Hallsville Junior School was hidden after Winston Churchill’s war cabinet ordered a cover-up to prevent unrest and a propaganda triumph for Hitler.

Most of the dead were never ­recovered and the crater was filled in while the official death toll was given as 77.

Now newly-unearthed papers in the National Archives reveal the true horror of September 10, 1940 when the school crowded with refugees waiting to be ­evacuated for three days was hit and how Churchill’s ­government hushed it up.

Then Home Secretary Sir James Anderson was informed about the scale of the disaster the following day. But while he told Churchill at a Cabinet meeting about the raid he did not mention the death toll, merely reporting ­that “persons in the East End... had been rendered ­homeless”.

Hallsville Junior School is so-named because Hallsville is the previous name of Canning Town, in east London. The area is named after the first Viceroy of India, Charles John Canning, who suppressed the Indian Mutiny of 1857 about the time the district expanded.

Yet even in 1940 there was fury over the raid – even though the full scale of the disaster was not known – as the authorities had been warned THREE times that the school was a prime target.

One of the last known ­survivors of the raid is ­Pat Wardle, now 78, above, who fought her way out of the rubble to learn her mother, sister and grandfather had been killed.

“It took me years to accept my mum was never coming back – I used to wait for her at the garden gate,” said Pat last week.

She was just eight when Hitler ­unleashed the Blitz on London – 76 consecutive days and nights of ­bombing to ­destroy morale and soften up the ­country for an invasion.

The attacks were concentrated on the East End, where thousands of poor ­working class families lived close to the docks. The first night left the capital in flames, covered in craters and with the dead piled up in the streets.

Pat lived with her mum Eileen, 32, baby sister Valerie, two, and dad Richard Barber, a stoker in the navy, in the ­upstairs room of a Victorian terrace close to the river. Her grandparents Hannah and Thomas Meadows, a ship scraper, lived in a room below.

“Before he was called up my dad built us all a brick shelter in the back garden,” said Pat, who now lives in Rainham, Essex.

“My mum couldn’t stand it though, didn’t want to be in it. Then the bombs came and neighbours told us everyone was going to the school from where we would be evacuated.”

Grabbing a few belongings and the dog, Pat’s mother and ­grandparents rushed to the school in Agate Street, Canning Town, along with ­other terrified families.

“There were so many people that the crowds just pulled us apart,” said Pat.

“I was with my friend and her mum, and I remember her calling out to my mum ‘It’s all right Eileen, she’s with me’. I looked down this school corridor and saw my mum ­holding my ­sister on her hip, and that’s the last I saw of them.”

The remains of Hallsville Junior School after it was bombed

The desperate East Enders spent three nights crammed into the school’s ­basement, waiting for transport while the city burned outside.

But after a series of official blunders the buses never ­arrived. On the fourth day a ­parachute bomb hit the school. The two-storey concrete building split in two and fell into the basement.

An anonymous rescue worker whose account is in the archives at Stratford Library said there were at least 600 people packed inside the basement. He left for fresh air just as the bomb dropped, making a 20ft-deep crater.

He wrote: “I saw half the school ­disappear in a cloud... there wasn’t much we could do.”

The rebuilt school today

One of a handful of eyewitnesses still alive, George Goff, below, now 80, said: “There were hundreds trapped – they were calling out from under the rubble. Then it was silent so rescuers could listen for survivors but after a few days they had to give up. Many are still there today.”

Pat scrambled her way out, and found her grandmother Hannah. Together they looked for the rest of their family, but eventually realised they were the only two to survive.

Angry East Enders were so incensed they staged a sit-in at the Savoy Hotel, and broke into padlocked Tube stations. Fearing an uprising Sir James opened up the underground for shelters.

The crater at Hallsville Junior School was tarmacked over, and in 1948 a new school was built on the site. The Queen Mother unveiled a plaque there in 1990.

Witness: George Goff

The 77 bodies that were found - ­including those of Pat’s family - were identified and buried in a mass grave at East London Cemetery where Pat, who is now a widow, laid flowers last week.

Pat said: “I’ve had a good life, a ­wonderful husband, two children and five lovely grandchildren which I never would if I’d stayed with my mother in that school corridor.

“When my nan and I went back to the house to get our belongings, we found my dad’s brick shelter in the garden was still standing. We’d all have survived if we’d stayed there.”