London - Relatives of two alleged hitmen in the London murder of a Pakistani politician have appealed for their extradition to Britain so they can clear their names.

The families said Khalid Shamim and Syed Mohsin Ali were “under duress” from Pakistani security officials when they testified that they had travelled to London to commit the 2010 killing of Imran Farooq . They called for the pair to be sent to the United Kingdom to receive a fair trial.

Details of the so-called “confessional statements” made by the alleged hitmen to a closed court hearing in Pakistan were described to The Telegraph this week.

They described how Mr Farooq, an exiled leader of the controversial Muttahida Qaumi Movement (MQM), was stabbed to death outside his north London home on the orders of rival British-based party leaders.

“I have no doubt that Khalid Shamim gave his confessional statement under duress,” Beena Khalid, wife of Mr Khalid, told the Telegraph. “A person in the detention of the security agencies for the last six years, facing torture, will do what security agencies want.”

“I believe that Mohsin Shah also gave a statement under duress,” added Majid Ali Syed, brother of Mohsin Ali. “I appeal to the British authorities to bring Mohsin Shah to the UK for the investigation and trial.”

In their confessions, the alleged hitmen said that the murder plot was ordered because Mr Farooq was deemed a “potent threat” to the MQM leadership, from whom he was believed to be planning to form a breakaway faction.

Khalid said that they operated under the direction of a senior lieutenant of Altaf Hussain, the powerful London-based head of the MQM.

Sources from Pakistan’s federal investigation agency (FIA) denied the claims of duress and torture. "The claim from Beena Khalid is baseless and there is no reality in it," they said.

Islamabad has been exerting pressure on Britain to bring charges against Mr Hussain over the murder, and recently filed a court report naming him and other party leaders as co-conspirators in the murder for the first time.

All statements and images of Mr Hussain are subject to a media blackout in Pakistan, imposed following his outspoken criticism of state institutions.

On Tuesday, MQM supporters staged widespread pro-Altaf Hussain rallies across Karachi.

Although no extradition treaty exists between Britain and Pakistan, it is possible that Khalid and Mohsin Ali could be handed over by Islamabad, as individuals can be extradited on a case-by-case basis.

Mohsin Ali’s arrest last year while trying to cross into Pakistan from Afghanistan followed a tip-off by Scotland Yard, whose records showed he had left the UK on the night of the murder.

According to his wife, Khalid had already been in Pakistani detention since 2011 following his arrest in Karachi. She denies he ever visited the United Kingdom, despite his confession.

Both families have also vowed to challenge the admissibility of the confessions at country’s Supreme Court.