Lawyers for radical cleric Abu Hamza are asking the High Court for time to carry out further medical tests as he renews his long-running legal battle to halt his extradition from the UK to the US.

The lawyers plan to seek a temporary injunction pending a request for an MRI scan to be carried out due to his "deteriorating health".

In papers before two judges in London, Hamza's QC, Alun Jones, argues that there is "uncontradicted medical opinion that a scan is medically necessary". Mr Jones adds: "If the applicant (Hamza) is unfit to plead, or arguably so, it will be argued that it would be oppressive to extradite him within the meaning of Section 91 of the 2003 Extradition Act."

The QC says a judge referred to Hamza's "very poor health" at an extradition hearing in 2008. "Over four years later, it appears there has been, or may have been, a further deterioration, perhaps attributable to sleep deprivation and the continued confinement of the appellant in an unrelentingly harsh environment. The responsibility of the (Home Secretary) is a relevant factor here."

Hamza is fighting extradition to the US on terrorism charges along with other terror suspects.

Mr Jones says in his written submissions that, after further medical tests are carried out and considered by doctors on both sides, "there may be no issue", but at present "it cannot possibly be said there is no issue" and the medical tests should be carried out.

Meanwhile, terror suspects Babar Ahmad and Syed Ahsan are to challenge a decision of the top prosecutor in England and Wales not to consent to them facing private prosecutions in the UK. Both are fighting extradition to the US where they are wanted on terrorism charges.

Keir Starmer, the Director of Public Prosecutions (DPP), said on Monday that the documents provided by the would-be UK prosecutor - British businessman Karl Watkin - were "very short, lack any meaningful detail and do not provide any real support for a prosecution".

Phillippa Kaufmann QC, appearing for both men, announced at the High Court in London that they intended to seek a judicial review on the grounds that the DPP had reached "an unlawful decision". Ms Kaufmann made the announcement as Ahmad and Ahsan joined other terror suspects, including radical cleric Abu Hamza, in a separate legal challenge to the Home Secretary's decision to sanction their extradition.

Mr Watkin, a campaigner against the UK's extradition arrangements with the US, made the attempt to bring legal proceedings against the pair in the UK to avoid "outsourcing the country's criminal justice system" to the US.