Archbishop Emeritus Desmond Tutu has urged Prime Minister Gordon Brown to take action against Robert Mugabe's regime in Zimbabwe for ongoing human rights violations in the country.

The Nobel peace prize winner criticised past efforts saying the "quiet diplomacy" pursued by the Southern Africa Development Community (SADC) had "not worked at all".

He called on Britain and the West to increase pressure on SADC to set firm deadlines for action, and to impose harsh consequences if conditions for improvement are not met.

The Archbishop said: "All of us Africans must hang their heads in shame for having allowed such a desperate situation to continue almost without anybody doing anything to try and stop it.

"It's been deeply, deeply distressing, the kinds of things that have happened to ordinary people in Zimbabwe. People are being detained and human rights are being violated without any conscience at all.

"The people are doing as much as you possibly could in such a ghastly situation. They have suffered enough. It is we who are on the outside who ought to intervene."

Archbishop Tutu made the comments to ITN, as he looked particularly to the British Prime Minister to bring about a "more effective intervention".

The International Crisis Group, a respected think-tank has backed the call for action against the African country, saying that the country's economic crisis had brought it "closer than ever to complete collapse" with inflation running at nearly 7,000 per cent. ICC called on the SADC to persuade Mugabe to step down amid the crisis.

The ICC report stated: "Some SADC leaders remain Mugabe supporters, and there is a risk the organisation will accept cosmetic changes that further entrench the status quo."

Possible incentives for retirement could include "immunity from prosecution for Mugabe and other senior Zanu-PF officials", the report said.

In addition, it urged for "guarantees, at least to a specified level, that the accumulated wealth, including land, of Mugabe, his family, and other members of the establishment will be secure".

"Zimbabweans want above all an end to their nightmare," it added, but said EU and US measures were ineffective.

"Western sanctions - mainly targeting just over 200 members of the leadership with travel bans and asset freezes - have proven largely symbolic.

"And general condemnations from the UK and US if anything [are] counterproductive because they help Mugabe claim he is the victim of neo-colonial ambitions."

Meanwhile in Harare, the Movement for Democratic Change struck a landmark deal with Zanu-PF to change the country's electoral laws. The constitutional amendment abolishes President Mugabe's right to appoint 30 MPs, removing a major hurdle to an opposition party winning an election.