British lawyer Stephen Gentle said the ailing health of the 83-year-old general was "an increasing cause for concern".

Lawyers will decide in "the next few days" whether more medical tests should be performed on General Pinochet, said to be suffering from a dozen illnesses including depression.

The news comes as a Spanish legal team prepares to meet the general for the first time at the rented Surrey mansion where he is under house arrest.

Jose Maria Stampa Braun and Fernando Escardo will prepare a defence to the human rights abuse charges the former dictator faces in Spain.

Mr Gentle described the approach as "twin track".

He said: "He's continuing to fight extradition from this country, but his Spanish lawyers are preparing his defence."

An unnamed member of Pinochet's UK legal team is reported to have said: "It is certainly true that we are considering raising the issue of our client's health, but no final decision has been made.

"The general perception is that his health has deteriorated recently, and it is in our view that it is in all parties' interests for that situation to be properly addressed."

General has 'dozen illnesses'

Further tests could prove Pinochet is unfit to stand trial

After nearly a year of wrangling, formal extradition proceedings start in a London court on 27 September.

A medical report ordered by the Chilean Government and signed by Pinochet's personal doctor, Helmuth Hernandez, and a local doctor Michael Loxton, detailed 12 illnesses affecting him.

They included diabetes, heart disease, prostate problems, arthritis of the left knee and mild asthma.

Amnesty International, which has campaigned for Pinochet's extradition, said the only evidence of his ill-health which could stop the legal process would be a report from a court appointed doctor.

More than 3000 people were killed or went missing during Pinochet's 1873-1990 dictatorship.

The extradition proceedings against him relate to charges of torture and conspiracy to torture.

He also faces 30 lawsuits in Chile.