The battle to extradite General Augusto Pinochet to face charges of human rights abuses and torture has returned to the British courts.

Belgian authorities and six human rights organisations are trying for a second time to challenge a decision by UK Home Secretary Jack Straw to free the former Chilean dictator on grounds of ill health.

If their action fails, the general could be given the green light to leave the country within a matter of hours.

Last week a court threw out their first attempt to overturn the decision, which was based on a claim that Mr Straw's refusal to release medical evidence was a breach of natural justice.

Application refused

Mr Justice Maurice Kay had said he was "completely against" the argument to disclose the report and the application "must be refused".

On Monday Belgium - one of four countries demanding the 84-year-old's extradition - returned alongside Amnesty International and five other human rights organisations to have its appeal against Mr Kay's verdict considered.

Three judges are hearing the appeal, thought to be the last legal barrier to the general's release.

Mr Straw prompted the original challenge by declaring he was "minded" to release the general after considering independent medical reports.

He is expected to announce his final ruling shortly after the court makes its decision.

General Pinochet has been fighting extradition to Spain since he was arrested more than a year ago after coming to the UK for medical treatment.

A Chilean jet is on standby at RAF Brize Norton waiting to take the general home if he is released. Meanwhile, he is expected to remain under house arrest at the Wentworth Estate in Surrey, until the final ruling.

However, any triumph secured by the general may be soured by a decision last week by a Chilean judge to accept a new lawsuit against the general based on torture charges.

A group of 643 ex-political prisoners in Chile filed the suit with judge Juan Guzman in Santiago last week.

But many human rights advocates say a trial in Chile is unlikely because Pinochet has parliamentary immunity as a life senator.