A court has overturned the death sentence of a British man who had been convicted for the murder of journalist Daniel Pearl in Pakistan nearly two decades ago.

Ahmed Omar Saeed Sheikh was handed seven years in prison instead for kidnapping, one of his lawyers said on Thursday, but could be freed in the coming days as he has already served 18 years on death row.

He was convicted of murdering 38-year-old Mr Pearl in 2002, who was investigating Islamic militants in the port city of Karachi after the 9/11 attacks.

The Wall Street Journal South Asia bureau chief was researching their links with Richard Reid, a terrorist who tried to set off a bomb in his shoes on a flight to Miami, at the time of his death.

Mr Pearl was kidnapped in January 2002 and confirmed dead several weeks after after footage emerged allegedly showing his beheading.

As well as overturning the death sentence, the Sindh High Court has also acquitted Fahad Naseem, Sheikh Adil and Salman Saqib, who had all been sentenced to life in prison for the case.

Speaking about British-born Sheikh, defence lawyer Khwaja Naveed said: “The court has commuted Omar’s death sentence to a seven year sentence.

Wall Street Journal reporter Daniel Pearl was abducted and murdered in Karachi in January 2002 (AFP)

“The murder charges were not proven, so he has been given seven years for the kidnapping.”

Given his time in prison in southern Hyderabad on death row, he could go free unless the government chooses to challenge the court decision, Mr Naveed added.

A Sindh prosecutor said he would consider appealing against the court decision.

“We will go through the court order once it is issued, we will probably file an appeal,” Faiz Shah, the provincial prosecutor general, said.

Sheikh, who was born in Britain and studied at the London School of Economics, was previously arrested in India in the 1990s for his involvement in the kidnapping of western tourists in 1994.