In an unprecedented move, the Prince has written to the Prime Minister of Pakistan appealing for clemency for Mirza-Tahir Hussain, who is due to be hanged during the Prince’s first tour of the country.

Hussain, 36, has been on death row in Rawalpindi for ten years after he was found guilty of murdering a taxi driver. The former Territorial Army officer from Leeds had been acquitted by Lahore’s High Court but the case was referred to a religious court which reversed the decision and sentenced him to death.

The Prince and the Duchess of Cornwall are due to arrive in Pakistan just three days before the execution is due to take place on November 1. He wrote to the Prime Minister, Shaukat Aziz, this month after guidance from the Foreign and Commonwealth Office and his advisers.

A spokesman at Clarence House said yesterday: “The Prince of Wales has been concerned about this case for some time and has raised it with the Prime Minister of Pakistan.”

Hussain’s brother, Amjad Hussain, said: “I think this is a highly significant move. My family is indebted to the Prince for his help.”

Under Pakistan’s parallel Islamic legal system, Hussain could be freed if the victim’s family accepts a “blood money” settlement. The family of the taxi driver, Jamshed Khan, had accepted almost £100,000 but later changed their minds.

Rab Nawaz Noon, the family’s lawyer, said: “The Government should not entertain this appeal. The family is not prepared to accept blood money. They want to see him [Hussain] hang for the crime he has done.”

Tony Blair told the Commons that there would be “very serious” consequences if the execution went ahead. The comment has been interpreted as a threat to recall the British High Commissioner from Islamabad, although it is unlikely that Mr Blair would want to damage relations with a key ally in the war against Islamist terrorism.

Hussain was 18 when he left West Yorkshire in December 1988 to visit relatives in Pakistan. Three days after arriving he took a train from Karachi to Rawalpindi and then hailed a taxi for the journey to his family’s village.

Later that night he led police to the body of the taxi driver. He told them that the driver had tried to sexually assault him and pulled a gun, and that during a struggle the weapon went off and killed the driver. He was convicted of murder and has been in custody since.

Mr Hussain’s MP, Greg Mullholland, has urged the Prince to cancel his trip unless the execution is stopped. But the Clarence House spokesman said: “We will act in accordance with Foreign Office advice.”

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