Mr Henderson spent his 32nd birthday as a hostage

Mark Henderson and his fellow captors are expected to be taken out of the jungle by helicopter on 22 or 23 December, said Monsignor Hector Fabio Henao.

It follows his meeting with Colombian president Alvaro Uribe and further discussions with the National Liberation Army (ELN) central command, which gave the green light for the release.

Mr Henderson's parents, who live near Pateley Bridge in the Yorkshire Dales, have said they are "cautiously optimistic" he will be released in time for Christmas.

Wait for news

Sharelle Henderson said: "We are told they are hoping he'll be released on Monday or Tuesday.

"The Foreign Office have heard this from the Monsignor and we are obviously just waiting and hoping."

Mrs Henderson and her husband, Christopher, have previously described the "emotional rollercoaster" they have experienced when the rebels have gone back on previous release promises.

But she said: "This time we are cautiously optimistic."

The release of the five foreigners had looked in doubt after President Uribe refused to create a military neutral zone in the Sierra Nevada mountain region.

But it is understood there has been some movement on the presence of troops which has led to the latest announcement.

Mediators had called for a halt to military operations to allow the handover of the hostages, who have been held since 12 September.

A Spaniard and a German were freed by the rebels three weeks ago, while Briton Matthew Scott, 19, of Fulham, south London, managed to escape.

Diplomatic plea

President Uribe met Monsignor Henao and the independent commission that published a report highlighting massacres, torture and abductions in the northern Sierra Nevada region.

The commission said urgently-needed food and medicines were being prevented from reaching the region by the continued fighting.

It called on the Colombian Government to introduce emergency aid into Sierra Nevada, and not just intervene there militarily.

On Thursday, United Nations Secretary General Kofi Annan called on the country's left-wing guerrilla groups to resume negotiations towards ending four decades of civil conflict.