Prime Minister: Syria must answer for UK surgeon's death

A letter from the Prime Minister to the mother of Dr Abbas Khan has called the surgeon's death a "sickening and appalling tragedy" and says the Syrian regime must "answer for it".

The letter, dated December 20, finishes with a handwritten note saying: "You are in our thoughts and prayers".

Watch: UK 'must ask Syria why they have let this happen,' says sister

A hand-written note at the bottom of the Prime Minister's letter to Mrs Fatima Khan says "You are in our thoughts and prayers".

The letter, dated December 20, calls Dr Khan's death a "sickening and appalling tragedy" and adds that "it is right that the Syrian regime should answer for it".

Read the full letter here

Dr Abbas Khan's sister, Sara, has told ITV News that she expects the British government to get answers from the Syrian regime. "This is the least they can do," she added.

Read: Independent post mortem of British surgeon expected

The sister of the British surgeon Dr Abbas Khan who died in Syria said that the Prime Minister has sent the family letters.

Sara Khan told ITV News that David Cameron said "he is now going to help us get answers but nothing has actually been said as to how they expect to do this and when".

Watch: British surgeon's mother: 'Why did they kill my son?'

Scotland Yard is to be involved in the post-mortem process surrounding the death of British doctor Abbas Khan, the family's solicitor has said, after his body was flown back to the UK.

Nabeel Sheikh issued a statement which read:

The family of British surgeon Abbas Khan have employed an independent pathologist to oversee the post mortem on his body following his death in a Damascus prison.

Nabeen Sheik, a lawyer for the family said the results of the post mortem were expected tomorrow.

The body of Dr Khan was returned to the UK today.

Watch - British surgeon's mother: 'Why did they kill my son?'

The mother of a British surgeon has demanded answers after accusing Syria of "killing" her son following his death in a Damascus prison.

The circumstances in which Dr Khan, a 32-year-old orthopaedic surgeon from London, died while in detention in Syria remains in dispute.

Speaking after his body arrived back in the UK Fatima Khan said: "I don't know why they killed my son and I want to ask why. Why on the release date they killed my son, I want answers. They are liars, every ministry is liars in Damascus."

Background: Mother of British doctor accuses Syria of 'killing' her son

British surgeon Abbas Khan's body is being flown to London this morning, just days after he was found dead in his cell. Syrian authorities have claimed that the surgeon from Streatham in South London took his own life, but his family insist he was murdered.

Mr Khan was arrested 48 hours after arriving in Syria last November.