Letters revealing fate of Syria's 'disappeared' mark victory for Assad

• Video report by ITV News International Affairs Editor Rageh Omaah

Dreaded letters revealing the fate of Syria's 'disappeared' population, those imprisoned by the government at the start of the country's civil war, have been received by families.

The letters sent by the Syrian government have informed the families of 836 arrested protesters, who went missing at the start of the Syrian revolution in 2011, that their loved ones have died in prison.

It is thought 81,652 demonstrators were arrested by government forces battling to keep President Bashar al-Assad in power, and many of them have not been heard of since.

Many families expected their loved ones had died in prison, but until recently they had been forced to cling onto the hope that they may still be alive. Now the Syrian regime is starting to reveal the names of those who died in its hands.

Kholoud Helmi, part of a group of Syrian exiles in London campaigning to find out what happened to their arrested loved ones, has just been told her cousin Ahmed died in prison.

She has a photograph of the letter she received but decided not to reveal its content because she hopes brother Ahmed, who is still being held, may be released.

She said: "When we received that news it was devastating but the fear is that we have other members in the family who are still in prison, so just to live that fear again and to receive other names, you don't know whether you're going to know or not."

Pictures smuggled out of Syria and obtained by Amnesty International show some of the grim detention cells Assad's prisoners were kept in before they were tortured and died.

A vigil was held in London to show respect of the dead and to highlight the plight of their loved ones who were arrested and may still be alive in jail.

Ms Helmi believes releasing some of the names is part of a deliberate policy by Assad, who has crushed most opponents, to indicate his forces have won the civil war.

She said: "It's came at a time when the Syrian revolution was at its weakest point. This came as a slap in the face, like hey see 'I got rid of you, I killed your dream so anyone in the country who dare to say anything in the future, this is what's going to happen to you.'"