Abdel Hakim Belhaj, a military commander in Libya and former dissident, is taking legal action against Jack Straw. Belhaj, a former dissident, was flown to one of Muammar Gaddafi’s prisons in a rendition operation in 2004, alleges that Straw, who was foreign secretary at the time, was complicit in the torture he suffered in Libya. Here is your full guide to the case.

What are the accusations?

In 2004, Belhaj was the leader of the Libyan Islamic Fighting Group, which opposed Gaddafi’s regime. MI5 believed that the group had links to al-Qaeda.

Belhaj claims that he and his pregnant wife, Fatima Bouchar, were detained by CIA agents in Bangkok as they attempted to travel to Britain to claim political asylum. He says that they were taken from Thailand back to Libya, via UK-controlled Diego Garcia, and alleges that they were tortured both during the rendition process and in Libya, where he was imprisoned.

Crucial to this case is the complicity of Britain in providing the intelligence necessary for the rendition process.

Belhaj and his wife accuse Straw of being complicit in the "torture, inhuman and degrading treatment, batteries and assaults" they suffered at the hands of Thai and US agents, and the Libyan authorities.

What is the background?

This issue first surfaced last September, when documents found in an abandoned Libyan government office indicated that MI6, particularly the head of counter-terrorism, Mark Allen, had provided the intelligence that allowed the CIA to detain Belhaj and his wife in March 2004.

At the time, MI6 did not deny involvement. The Guardian quotes Whitehall sources as saying that the agency’s actions were part of "ministerially-authorised government policy".

Why is Jack Straw liable?

Belhaj’s lawyers say that Straw was foreign secretary with responsibility for MI6 at the time of the rendition. They also allege that a 2004 letter from Allen to Libya’s former intelligence chief congratulated Libya on Belhaj’s safe arrival.

Straw is not the only person to face legal action. Papers have already been served in the High Court to sue the UK government, its security forces, and Allen, for damages.

The papers served against Straw allege his complicity in the torture that Belhaj and his wife suffered, as well as misfeasance in public office. They are seeking damages for the trauma.

Why now?

Belhaj’s lawyers decided to serve papers on Straw after a report in the Sunday Times on 15 April which claimed that Straw allowed the incident to happen. The newspaper claimed that Straw admitted that he had approved Belhaj’s secret rendition after MI6 agents presented him with evidence proving that he had signed it off.

What has Straw said on the matter?

Speaking to the BBC’s Today programme last autumn, when these allegations first surfaced, Straw said:

The position of successive foreign secretaries, including me, is that we were opposed to unlawful rendition, opposed to torture or similar methods and not only did we not agree with it, we were not complicit in it, nor did we turn a blind eye to it.

While UK ministers have denied any complicity in rendition or torture, Straw has not commented further, because of the ongoing police investigation into the UK’s alleged role in illegal rendition. The Crown Prosecution Service launched this criminal investigation earlier this year, and Straw already faces questioning.

What next?

Leigh Day and Co, the law firm representing Belhaj, said that they expected Straw’s response to the letter of claim would echo previous responses from government solicitors, which “neither confirm nor deny”.

Due to this, they are seeking a response by close of business on 17 May, as opposed to the six months normally allowed to respond to allegations. They said that after this date, proceedings could be issued without further notice. This would place Straw in the uncomfortable position of defending his actions in court.

If Straw does not admit liability in this time, the law firm said that they expected him to provide the documents detailed in the Sunday Times article, and copies of government communications relating to Belhaj’s case.