The High Court will today hear the application by the Government for a declaration that a ‘closed material application’ may be made in the legal claim brought against Mr Straw and Sir Mark Allen as well as the security services over allegations that they were both unlawfully involved in the illegal rendition of Mr Belhaj and his pregnant wife to Gaddafi’s Libya in 2004.
Lawyers for Mr Belhaj from law firm Leigh Day will argue that this is unnecessary and is not in the interests of the fair and effective administration of justice and that given thestrong public interest in the claim which concerns alleged UK official involvement in abduction and torture, other less draconian methods should be used to deal with sensitive material.
In January 2017, the Supreme Court unanimously dismissed the Government’s appeal to have the case thrown out, concluding that the claims that they were unlawfully involved in the rendition of Mr Belhaj and Mrs Boudchar, and are culpable for the torture they allegedly suffered, must be allowed to proceed in the English courts.
The defendants had gone to the Supreme Court to get the legal action dismissed on the grounds of ‘State Immunity’ and ‘Foreign Act of State’. Under the principle of State Immunity, foreign states or foreign officials may not be sued in the English courts.
In the Supreme Court judgment Lord Sumption noted that the case involved a “combination of violation of peremptory norms of international law and inconsistency with principles of the administration of justice in England which have been regarded as fundamental since the 17th century”. Belhaj v Straw  2 WLR 456 at 
Libyan politician Abdul-Hakim Belhaj, a political opponent of Colonel Gadaffi, and his pregnant wife Fatima Boudchar were both victims of illegal rendition to Libya in March 2004.
The Supreme Court Justices unanimously held that, although the claims of Mr Belhaj and Mrs Boudchar would require findings to be made that officials of the US, Malaysia, Thailand and Libya had acted unlawfully to succeed, their claims should nevertheless proceed in the English courts.
Sapna Malik from law firm Leigh Day said:
"In a case of this importance, and where so much relevant evidence is already in our clients' possession, it is vital that they are able to participate in the trial of their claims as fully as possible and not be shut out of the process."
In 2004 Mr Belhaj was leader of the Libyan Islamic Fighting Group, opposing Colonel Gaddafi when he was detained in Malaysia then Thailand, before being illegally rendered back to Libya.
Mr Belhaj states that he was hooded and shackled to the floor of the plane in a stress position, unable to sit or lie during the entire 17-hour flight back to Libya where he was detained for six years in some of the country’s most brutal jails.
He claims to have been interrogated by foreign agents, including some from the UK.
The allegations against the security services and Mr Straw arise from documents discovered after the fall of Colonel Gaddafi's regime, when documents were discovered in the headquarters of the fallen regime’s intelligence agency. In a fax apparently sent from MI6 to the Libyan intelligence services on 1 March 2004, MI6 informed the Libyans of the couple’s then whereabouts in Malaysia.
The couple were rendered to Libya, via a tortuous stay in a secret detention facility in Thailand, approximately one week later.
Then, in a letter from Sir Mark to Moussa Koussa, head of Gaddafi's intelligence agency, dated March 18 2004, Sir Mark passes on thanks for helping to arrange Tony Blair's visit to Gaddafi, writing: "Most importantly, I congratulate you on the safe arrival of Abu Abd Allah Sadiq[Mr Belhaj]."
He continues: "This was the least we could do for you and for Libya to demonstrate the remarkable relationship we have built over the years…. The intelligence about [Mr Belhaj] was British. I know I did not pay for the air cargo."
He was eventually released in 2010.
Ms Boudchar was imprisoned in Libya for four months. She was released just three weeks before giving birth, by which time her health, and that of her baby, was in a precarious state.
Lawyers for Mr Straw and Sir Mark denied any unlawful conduct on their part and applied to have the claims dismissed on the basis that the English courts could not hear the claims due to the doctrines of State Immunity and Foreign Act of State.
A High Court judgment in December 2013 ruled that English courts should not hear evidence or rule on the case due to the Foreign Act of State doctrine, as the rendition had allegedly taken place with the assistance of other states including the US.
The judgment by Mr Justice Simon was appealed by Mr Belhaj and his wife, and in October 2014 the Court of Appeal, agreed that the case could be heard in an English Court.