It is one of the 20th Century's greatest mysteries. Did Grand Duchess Anastasia flee the execution which wiped out her family in Russia? Nigel Green investigates the theory that a North-East man helped her escape.

IT IS after the Russian revolution of 1917 and Tsar Nicholas II has been taken prisoner by the Bolsheviks, along with his wife Alexandra and their five children. Held in a house near the Siberian city of Yekaterinburg, a guard orders them down to the cellar. They are to line up while they have their photograph taken.

But the Tsar and his family are murdered by a firing squad before their bodies are reportedly dumped down a mineshaft. The date, July 17, 1918, is written into the history books, the day the Russian royal family was massacred.

Today, the execution is renowned for sparking one of the biggest mysteries of the 20th Century - did one of the Tsar's daughters, the Grand Duchess Anastasia, survive, and if so, how?

According to reports, some of the children had been carrying diamonds hidden underneath their clothes, which could have shielded them from the bullets. Did the guards find 17-year-old Anastasia still alive and spirit her away to safety?

The son of a Royal Navy sailor from Middlesbrough believes he may know the answer. Ronald Shaw, who lives in Ormesby, has come forward to reveal how his father claimed to have taken part in the rescue of Anastasia.

Numerous theories have been put forward and even people claiming to be Anastasia have surfaced during the past 90 years. But the mystery of what happened to her has still not been solved.

Archaeologists recently claimed they may have found the bones of Anastasia and her brother, Crown Prince Alexei, in a forest in Russia. The news prompted Ronald to reveal the tale his father, Jack, told him.

At the start of the First World War, Jack lied about his age to join the navy at 15. He served as a stoker on the cruiser HMS Diana and, towards the end of the war, saw service off the coast of China, taking part in raids on vessels smuggling opium.

After serving for three years, his father was going on leave and went ashore at Hong Kong to catch a ship back to Britain.

"It was then he and 11 other Royal Navy sailors were individually taken into a room by some officers," Ronald says. "They were given a few shillings and told to buy some old clothes from a nearby market. They were told not tell anyone they were in the Royal Navy when they got on the ship.

"They were then put onto a huge passenger ship called the Empress of Asia. They weren't even allowed to tell the merchant seamen who they were."

Ronald's father told him the vessel had sailed to the Russian port of Vladivostok and that, when the ship docked in the morning, it was surrounded by guards armed with pick-axe handles.

Around 30 children went on board the ship and it sailed later that day.

"My father was asleep when the children came on board," he says. "He didn't even know they were on the ship until they were well out to sea and the children came up on deck. It was rumoured that one of the girls had been given the captain's cabin. He recalled one of the other men saying: "Who do they think they are - royalty?

"My father also told me how a concert show was put on for them and he noticed how one of the girls was sat on a chair in the middle, with a gap between her and the other children. Wherever she went, she was guarded by two men and a woman.

"He never saw her very close, but when he later looked at pictures of Anastasia, he said she looked like the girl he had seen."

Jack later told his family how their ship sailed to Vancouver in Canada, where the passengers disembarked and were put on a train.

After arriving back at Devonport barracks, Jack and his comrades read about the death of the Tsar and his family. "He heard that Anastasia might have got away and it was then that he realised it could have been the girl he saw on that ship," says Ronald.

After the war, Jack returned to Middlesbrough and worked in the steelworks. He and his wife Maude had eight children, including Ronald, who is the youngest. Jack died in 1979.

Ronald, a retired dock worker, says: "My father was a very sensible and level-headed man - not the type to make up stories. But he was convinced he had helped rescue Anastasia or, at the very least, the girl had been a decoy.

"He believed he and the other sailors may have been originally sent to Vladivostok in the hope they could rescue all the Russian royal family but that wasn't to be. The reason it would have been top secret was because the British government could not have been seen to have been helping the Russian royal family. King George V had already made it clear they could not come to Britain.

"My father used to say that, if they ever found the bodies of the Russian royal family, Anastasia's would be missing."

In 1991, archaeologists dug up the remains of the Tsar, his wife and three of their children. DNA tests proved the skeletons belonged to the Russian royal family. However, the identities of the children's bones were never firmly established and it is believed Anastasia and Alexei may not be among them. The bones were laid to rest in St Petersburg.

Ronald says: "I'd love to know what happened to that girl. Perhaps she ended up in Canada. It would have been an ideal place for her to go - a huge country that was also part of the British Empire. The king had said they wouldn't come to England but that wouldn't have stopped them going to Canada.

"Maybe there are files or papers somewhere that could finally prove what top-secret mission my father's ship was on. It would be great to solve this mystery once and for all."