Robert Mugabe was stripped of his honorary knighthood today over his "abuse of human rights" and "abject disregard" for democracy, the Foreign Office said.
The move comes as the Zimbabwean leader faces condemnation from around the world ahead of Friday's presidential run-off.
Prime Minister Gordon Brown revealed today that he was seeking to block a Zimbabwe cricket tour of England planned for next year.
The Queen has now approved the annulment of Mr Mugabe's knighthood - awarded in 1994 - on the recommendation of Foreign Secretary David Miliband.
A Foreign Office spokesman said: "This action has been taken as a mark of revulsion at the abuse of human rights and abject disregard for the democratic process in Zimbabwe over which President Mugabe has presided."
In Zimbabwe, the opposition leader emerged briefly from his refuge in a foreign embassy today to call on African leaders to save his country.
Morgan Tsvangirai, who has withdrawn from Friday's run-off presidential ballot, also said Zimbabwe needs UN peacekeepers to help prepare the way for new elections.
Mr Tsvangirai returned to the safety of the Dutch Embassy in Harare following a news conference, a measure of continuing tensions in the country.
The leader of the Movement for Democratic Change party said the goal of the talks he was proposing would be to form a coalition transitional authority in Zimbabwe.
He also said discussions could not begin until there was an end to attacks on his supporters, blamed on President Robert Mugabe's government.
Mr Tsvangirai also wants a release of "political prisoners," including the MDC's No. 2 Tendai Biti, who has been jailed since earlier this month on treason charges that can carry the death penalty.
"What is important is that both parties must realize the country is burning and the only way is to sit down and find a way out of it," Mr Tsvangirai said at his home in Harare after leaving the embassy.
He looked relaxed, smiling and joking often. He then returned to the embassy.
Zimbabwean Deputy Information Minister Bright Matonga said the government and Mugabe's ZANU-PF were focused on the election. Mr Tsvangirai's name will be on the ballot.
"There will definitely be elections on Friday," Matonga said.
Mr Tsvangirai fled to the Dutch Embassy on Sunday following his announcement he was withdrawing from the run-off. He sought refuge after getting a tip that soldiers were headed to his home.
Mugabe, by all indications intent on extending his nearly three-decade rule, has grown more defiant in the face of growing international pressure.
But Mr Tsvangirai said "the election is not a solution. What is a solution is some sort of transitional process to address the critical issues facing the country.
"We are making proposals Mugabe has to accept."
While Mr Tsvangirai did not spell out how the transitional body would work, he has insisted in the past that he lead, and Mugabe have no role in, any coalition.
Mugabe, though, is refusing to yield power. Mr Tsvangirai's claim to leadership is his first-place in a field of four in the first round of presidential voting March 29, although official results said he did not win the 50% plus one vote necessary to avoid a run-off.
Mr Tsvangirai's party and its allies also won control of Parliament - the first time since independence from Britain in 1980 that ZANU-PF failed to win a parliamentary majority.
Mr Tsvangirai said he was asking the African Union, whose heads of state hold a regular summit in Egypt next week, to take over mediation, which so far has been in the hands of South African President Thabo Mbeki and a southern African regional group.
Mr Tsvangirai had previously called on Mr Mbeki to step aside, accusing him of bias in Mugabe's favour and saying his "quiet diplomacy" was not working.
Mr Tsvangirai said the AU mediation he was proposing cannot "be a continuation of talks and talks about talks that have been largely fruitless for several years. The time for actions is now. The people and the country can wait no longer. We need to show leadership."
Earlier in the Guardian newspaper Mr Tsvangirai called for UN peacekeepers to help prepare the way for new elections. Asked about that in Harare, Mr Tsvangirai said: "What do you do when you don't have guns and the people are being brutalised out there?"
He stressed he was not calling for military intervention.
Deploying peacekeepers requires an international consensus that can be hard to build, and efforts can be blocked by governments expected to host contingents.
In The Guardian, Mr Tsvangirai acknowledged calling for international intervention was sensitive, but said it would offer "the best chance the people of Zimbabwe would get to see their views recorded fairly and justly."
"We do not want armed conflict, but the people of Zimbabwe need the words of indignation from global leaders to be backed by the moral rectitude of military force," he said. "Such a force would be in the role of peacekeepers, not troublemakers. They would separate the people from their oppressors."
Scores of opposition activists, including high-ranking party members, have been attacked or killed.
Regional heads of state, meanwhile, were meeting in Swaziland in hopes of finding a solution for Zimbabwe.Reuse content