UK Home Secretary Jack Straw is to make a statement to the House of Commons on the future of former Chilean dictator General Augusto Pinochet amid growing criticism of his handling of the case.

Mr Straw is "minded" to refuse General Pinochet's extradition to Spain after receiving medical advice that he is too ill to stand trial on torture charges.

The medical report by four doctors is being kept secret.

The move has been welcomed by the Chilean Government and the 84-year-old general's supporters.

But human rights campaigners and relatives of those who disappeared during General Pinochet's regime have questioned Mr Straw's handling of the case.

The home secretary is to answer a private member's question on the decision in the Commons at 1530 GMT.

He is likely to face tough questioning from Shadow Home Secretary Ann Widdecombe.

She has accused him of making contradictory decisions and said: "The same Jack Straw who arrested General Pinochet as he lay on his hospital bed recovering from an operation is the same man who has just let a war criminal walk out of the country before a police investigation into him was complete."

'Make medical report public'

Carlos Reyes, a spokesman for Chileans living in exile, said: "We are going to challenge Mr Straw's decision through every means possible and we are going to challenge the decision to keep the medical report secret.

"This report must be made public so we can be clear upon what grounds the decision has been made."

The Home Office said the "unequivocal and unanimous" conclusion of the medical team that examined the general on 5 January was that he was "at present unfit to stand trial, and that no change to that position can be expected".

The general could be flying home in a week, but his fate is subject to representations by Spain and other interested parties.

Meanwhile Chile's ambassador to London, Pablo Cabrera, said if the general was sent home, he was likely to be stripped of his immunity and taken before the courts.

Mr Cabrera added: "It is time for Chileans to resolve their own problems, particularly as democracy is strengthening in Chile."

But Ann Clwyd, Labour MP for Cynon Valley and chairwoman of the Parliamentary Human Rights Group, said she doubted he would ever be brought to trial in Chile.

She called on Mr Straw to release the medical reports and insisted it would not be a breach of doctor-patient confidentiality.

'Let Spanish decide'

"According to advice which I have obtained, legal precedent clearly allows for the release of such medical information, providing that it is in the public interest to do so," she said.

Mrs Clwyd said it should be up to the Spanish courts to decide if General Pinochet was fit for trial and added: "After all, nobody is suggesting that Pinochet isn't fit enough to travel the long journey home to Chile."

General Pinochet could still face prosecution in the UK, mounted either by the Director of Public Prosecutions or a through a private action brought by campaigners.

Former prime minister Baroness Thatcher, who has campaigned for General Pinochet's release since his arrest in London in 1998, said: "I would trust the home secretary's judgement. He is a very fair man."

Another supporter, former Conservative Chancellor Lord Lamont, welcomed the decision but added that it was "long overdue".

"It has never been in the interests of justice that General Pinochet should be tried in Europe - this has always been a matter for Chile," he said.