Lady Thatcher has been a vocal supporter of the former Chilean dictator who faces extradition to Spain for 35 charges of torture and conspiracy to torture.

The former prime minister has also visited General Pinochet at the home outside London where he is under house arrest.

She will call for the general to be released when she addresses the fringe meeting, Pinochet - Britain's Only Political Prisoner, in Blackpool on Wednesday.

Former Chancellor, Lord Lamont: "This meeting is about is doing what the government of Chile want"

Also addressing the meeting will be former chancellor Lord Lamont.

He told the BBC: "What this meeting is about is doing what the democratically elected government of Chile want and that is to return General Pinochet to his own country."

Lord Lamont: "A matter for Chile"

The meeting was not just in favour of the rights of General Pinochet but also the democratic rights of Chile, he said.

Lord Lamont continued: "One of the factors that strongly influences Lady Thatcher is the help that Chile and the government of that time under General Pinochet gave to this country during the Falklands [conflict].

"She feels strongly about the way he was arrested in this country, having been welcomed in this country by the government through the VIP lounge, and being arrested in hospital."

The former Chilean dictator was arrested in London a year ago on a Spanish warrant accusing him of orchestrating a systematic campaign of terror during his period in office from 1973 to 1990.

In March, the House of Lords ruled that General Pinochet could only be extradited for charges after December 1988, when Britain incorporated an international torture convention into law.

This left just one specific allegation of torture and one conspiracy charge from the original list of allegations by Spain, but Spanish judge Baltasar Garzon has since added 33 more torture charges.

Lord Lamont said that "no-one is going to defend torture and brutality" but the matter was one for the Chilean Government.

He said: "The Chilean Government has decided what sort of deal and reconciliation it wants with its political opponents in Chile.

"It is wrong and dangerous for us to interrupt that reconciliation process."

But Mark Latimer of Amnesty International warned against political interference in the case.

He said: "Pinochet faces 35 separate charges of torture and conspiracy to torture, including torture by beating, by burning, by asphyxiation, torture by sexual abuse and by electrocution.

"Together those allegations of crime constitute the most serious to come before an English court.