Mirza Hussain has been in jail for 18 years

Mirza Tahir Hussain is now due to be executed on 1 October. It is the third time his execution has been delayed.

His brother Amjad said the delay gave him and his family "a little relief" but at the same time it was extending their "uncertainty and agony".

Amjad Hussain has now called on Prime Minister Tony Blair to intervene in the case.

The British High Commission in Pakistan confirmed on Wednesday that 36-year-old Hussain had been granted a further stay of execution.

Hussain, who is of dual British-Pakistani nationality, has been in jail in Pakistan for 18 years for the killing.

He has always claimed he was acting in self-defence, saying the driver tried to sexually assault him.

There are serious doubts about the safety of Mirza Tahir Hussain's conviction and he still faces execution in a matter of weeks Tim Hancock, Amnesty International

Amjad Hussain said: "We did not ask for this stay. It shows that my brother's case has got the attention of the Pakistan authorities, but it seems they are still undecided as to whether President Musharraf will step in and stop an innocent man being executed or whether they will let this barbaric punishment go ahead.

"My brother did not commit the crime of murder that he has been convicted of. His trial was unfair and his detention in Pakistan for the last 18 years has destroyed all our lives."

Amnesty International UK campaigns director Tim Hancock said this further stay of execution was not enough.

"It does not address the facts that there are serious doubts about the safety of Mirza Tahir Hussain's conviction and that he still faces execution in a matter of weeks.

"We will continue to press the Pakistani authorities, for as long as it takes, until we know that Mirza Tahir Hussain will not, at any time, be executed. And we expect the UK Government to do the same."