Lawyers for a Scottish prisoner shot in Pakistan have repeated calls for the Prime Minister to ­intervene as it emerged he will spend a further two days in hospital being treated for his injuries.

Mohammad Asghar, 70, from Edinburgh, was targeted in Adiala prison in Rawalpindi last week, where he faced the death penalty after being convicted under blasphemy laws.

Legal action charity Reprieve said Mr Asghar, who suffers from paranoid schizophrenia, must not be sent back to jail but should remain in a secure medical facility where he can receive treatment in safety.

The charity said David Cameron now has a "short window of opportunity" to intervene.

Mr Asghar was jailed in January after writing letters claiming to be the Prophet Mohammed.

He received surgery after he was shot in the back by a guard on Thursday morning and remains in hospital.

An appeal has been lodged against his conviction, with lawyers pointing out that judges did not consider evidence of his mental illness.

Reprieve spokeswoman Maya Foa said: "Mr Asghar's two extra days in hospital mean there is a short window of opportunity here for David Cameron to step in and ensure his safety.

"The British Government must ensure that he is held in a secure medical facility where he can receive the treatment he so desperately needs, both for his recent injuries and his existing mental illness."

A Foreign Office spokesman said: "Consular officials visited Mr Asghar over the course of the weekend.

"We have previously raised our concerns about his case... and continue to do so at a senior level."