A 65-year-old British national faces the death penalty in Pakistan after a court in Rawalpindi found him guilty of blasphemy.

Mohammed Asghar, who was sentenced on Friday, was arrested in Sadiqabad in 2010 for writing letters claiming to be a prophet.

Asghar, a British national of Pakistani origin, has a history of mental illness according to his lawyers.

There was a trial but we are unclear as to what happened. Justice Pakistan Project, which represents the accused.,

He was charged under section 295-C of the Pakistani Penal Code. It states: “Whoever by words, either spoken or written, or by visible representation or by any imputation, innuendo, or insinuation, directly or indirectly, defiles the sacred name of the Holy Prophet Muhammad (peace be upon him), shall be punished with death or imprisonment for life, and shall also be liable to fine.”

Asghar's legal team said it was effectively prevented from representing him after the judge appointed state lawyers. It will file an appeal against the sentence.

A spokesman from the Justice Pakistan Project, which represents him, said: "There was a trial but we are unclear as to what happened. Blasphemy cases are heard in prison because it is too unsafe for them to be heard in open court. It is a security concern. We are not happy with the way the case proceeded. We didn't back out of the case."

The spokesman did not confirm whether it had contacted Asghar's family in Scotland. Nor would it give details on Asghar's mental illness, although it said there was documentary evidence of it.

The British High Commission told Al Jazeera: "We can't give any information, other than we are aware of the case."

The special court inside Rawalpindi's Adiala Jail, where Asghar is being held, rejected the defence team's claims that the 65-year-old suffered mental health problems.

Pakistani media reported that the public prosecutor, Javed Gul, produced a copy of the letters Asghar wrote and that four police officials gave evidence against him. Handwriting experts also gave evidence, saying the letters had been written by him.

Rights body, Amnesty International, has called for Asghar's "immediate and unconditional release".

"Mohammad Asghar is now facing the gallows simply for writing a series of letters. He does not deserve punishment...," said Polly Truscott, Amnesty International’s Deputy Asia Pacific Director.

The UK travel advisory for Britons travelling to Pakistan does not mention the blasphemy law; it only says visitors should remember that "laws reflect the fact that Pakistan is a Muslim country. You should respect local customs and sensitivities at all times, especially during the holy month of Ramadan or if you intend to visit religious areas."

The maximum penalty for breaking the country's blasphemy laws is death.

However, there has been an unofficial moratorium on civilian hangings since 2008 and only one person has been executed since then - a soldier convicted by court martial.

"The blasphemy laws undermine the rule of law, and people facing charges risk death and other harm in detention. Pakistan must immediately release Mohammed Ashgar and reform its blasphemy laws to ensure that this will not happen again," said Truscott.

A second British national, 72-year-old Masood Ahmed, was jailed in November on blasphemy charges after he was secretly filmed reading the Quran.

Ahmad belongs to the minority Ahmadiyya sect, considered to be heretics in Pakistan. They were declared non-Muslim in 1974 by the Pakistan government and have severely restricted religious practices, including a ban on quoting from the Quran.