Celebrities including Frankie Boyle, Al Murray and David Morrissey are among 70,000 who have signed  a petition for the release of a Scots grandfather on death row in Pakistan.

The daughter of Mohammad Asghar is taking the plea personally to Downing Street today asking David Cameron to intervene and is backed by public personalities including the comedians and the actor among many others, his supporters said.

Jasmine Rana has travelled from Edinburgh to present petition demanding action in the case of 70-year-old Mr Asghar who was convicted of blasphemy.

The grandfather and father of five, who has mental health problems, was the target of a shooting in Adiala prison in Rawalpindi last month.

His family, backed by the charity Reprieve, say his safety cannot be assured in Pakistan and he should be returned to the UK.

First Minister Alex Salmond said he is "extremely concerned" about Mr Asghar's welfare and said he would support a prisoner transfer agreement following a meeting with Ms Rana on Wednesday.

Family solicitor Aamer Anwar said: "It is no longer acceptable for the UK Government to hide behind a wall of silence whilst Mr Asghar's life hangs by a thread and we call upon the Prime Minister to personally and publicly hold the Pakistani government to account.

"Every minute that passes increases the risk to Mohammad Asghar's life.

"On Wednesday I and Jasmine met with the First Minister, Alex Salmond who promised to speak directly to David Cameron. I understand that phone call took place last night and the PM has confirmed his personal interest in the case. But David Cameron must understand that words are no longer enough, every second that Mohammad Asghar remains in Pakistan increases the likelihood of his death.

"Jasmine said today that her family has had enough of Pakistan's broken promises and is disappointed that Mr Cameron failed to meet with her. Yet her family cannot thank enough the thousands of people who have offered their solidarity and prayers for her father.

"The Prime Minister must now personally intervene with the Pakistani Government. They must understand that after four long years it is time to send home a seriously ill, old man Mohammad Asghar before it is too late."

Mr Asghar was sentenced to death in January after writing letters to a number of people claiming to be the Prophet Mohammed.

He was arrested in 2010 following a blasphemy complaint by a tenant with whom he was having a dispute.

The Scot had previously been diagnosed as suffering from severe paranoid schizophrenia but this was not taken into account by the authorities during his trial, Mr Anwar said.

A Downing Street spokeswoman said this week that the Government has repeatedly raised Mr Asghar's case "at senior levels" and is working to ensure that he is receiving the best possible support.

She said the Prime Minister had asked the minister for Pakistan Tobias Ellwood to meet Mr Asghar's family today.