Lord Nazir Ahmed and Baroness Sayeeda Warsi, Muslims from Britain's upper house of parliament, have shuttled between cabinet ministers and officials for two days trying to secure an amnesty for Gillian Gibbons, jailed for 15 days.

"The president will receive the British delegation tomorrow at 0730 GMT," Mahjoub Fadl Badri, Beshir's press secretary, told AFP.

He said the meeting would take place at the presidential palace in Khartoum, speaking after the British peers told reporters in a luxury hotel that they had decided to delay their departure over signs of progress.

"We will not be leaving tomorrow (Monday) morning at 5 am as we hoped," Warsi told reporters, vowing to stay on while hope remained for success.

"Some progress has been made. As a result of that progress and what we're hoping to achieve, we will not be leaving," she said, having spent the day waiting for a meeting with Beshir.

Gillian Gibbons © AFP/FR-HO/File

Ahmed, who said they had the support of Prime Minister Gordon Brown for their mission, said their intervention was "very important because first we are British, we are parliamentarians, and we are Muslims.

"We understand the situation and the culture of this part of the world and we also understand our culture and our norms and customs, and by playing this important role we think that we can offer help."

He said it was a "very critical time" and declined to elaborate on the difficulties encountered so far in order not to jeopardise Gibbons's fate.

Thousands of people demonstrated on Friday after the main Muslim prayers in Khartoum, the conservative capital of the former British colony, against what they considered Gibbons's lenient sentence, with some calling for her death.

Being found guilty of insulting religion and inciting hatred in Sudan is punishable by up to six months in prison, 40 lashes and a fine.

"We've had quite a number of meetings today. Probably some of the toughest meetings we've had so far," Warsi told reporters.

Earlier she said concerns about the teacher's well-being lifted after they met her on Saturday at the secret location where she is being incarcerated.

"I was concerned about her safety and her security and her well-being and as I left I was satisfied on all grounds," Warsi told AFP. "She's doing well, she's in good spirits considering the last seven days."

Sudanese demonstrators burn a newspaper bearing the story of Gillian Gibbons in Khartoum © AFP/File Isam Al Haj

"I'm really sad to leave and if I could go back to work tomorrow then I would," said Gibbons, who is due to be deported at the end of her sentence on December 9 if the peers fail to take her home earlier.

She was jailed for allowing primary school pupils in the Christian-run Unity High School to give the bear the same name as the Muslim prophet -- also a very popular boys' name -- as part of a school project.

Her arrest and jail sentence sparked outrage in Britain and a diplomatic crisis between London and Khartoum, which has strained relations with the West largely over nearly five years of war in Darfur.