Pyotr Vassilievich Mironov

He was a Russian nobleman, tsarist colonel and diplomat, was negotiating an arms deal in Britain and was stranded there, along with his family, during the Russian Revolution.

While his 7 sisters lived a privileged existence, splitting their time between the estate and Moscow, Pyotr joined the army.

During the First World War, he was an emissary of the last tsar, Nicholas II, and was sent to Britain to negotiate an arms deal with the Government.

But while there, the Bolsheviks staged their Revolution and he found his route back to Russia blocked.

He never returned - he did not dare while the Communists were in power. He remained in London, working as a taxi driver, until his death in 1957.

As Helen Mirren knows, his sisters stayed in touch with him via letters, keeping him informed of their changing fortunes and breaking the news that they had been expelled from the family estate.

Although she has never made those letters public, Mirren gave them to the novelist Helen Dunmore, who used them to write the Radio 4 drama called The Mironov Legacy.

Mirren herself starred as Pyotr's favourite sister, Ilyena. The play charted the struggle of a family torn apart and having to cope with utterly changed circumstances.

At the time Mirren said: "What really comes across is [my grandfather's] incredible pride and identification with his own personal story - with his nation, his Russianness, his military background - and I absolutely remember that about him.

"And, of course, he lost all of that. I think he lived in constant psychological pain."

The sisters kept in touch until the early Thirties. According to Zimina, after they were thrown out of Kuryanovo, Lydia and her daughters - their father died long before the Revolution - were briefly homeless before Ilyena managed to move the family to Moscow, taking care to conceal jewellery and other valuables from the Soviet secret police.

"A loyal peasant from their estate helped to hide the valuables in a haystack,' said Zimina. "But they were stolen from the haystack before the family could go back for them."

In Moscow, the Mironovs were immersed in the febrile atmosphere of revolution - keeping their heads down and steering clear of the Red Army.

Three of the sisters - Lydia, Valentina and Antonina - quickly married.

The other three - Ilyena, Zinaida and Ksenia - remained spinsters and lived with their mother until her death in 1928 in a cramped windowless flat - the same flat where Lydia's typing pool had been based.

"They supported each other,' said Zimina. "They were their own best friends."