Ministers were accused of "breathtaking double standards" for attempting to send thousands of failed asylum-seekers back to Zimbabwe, despite the government-sponsored violence there.
Campaigners expressed horror that the Home Office is pressing ahead with a High Court battle to deport up to 13,000 Zimbabweans despite warnings they face persecution if they are returned to their homeland because they have sought asylum in Britain.
Refugee groups will stage a final attempt on Wednesday to appeal against a ruling that could allow ministers to begin deportations.
Earlier this week, Gordon Brown denounced Robert Mugabe's regime as a "criminal cabal", while the Foreign Office warned against all travel to Zimbabwe. But No 10 yesterday told campaigners they "expect shortly to be in a position to enforce the return of those unsuccessful Zimbabwean asylum-seekers who have been found not to need the protection of the UK yet refuse to leave voluntarily".
Kate Allen, director of Amnesty International UK, said: "Gordon Brown has said 'Britain will not shirk our responsibilities to the people of Zimbabwe' and that includes those who have come here seeking our protection. No one should be sent back to Zimbabwe at the moment."
The Home Office has been battling in court for almost three years to win the right to deport failed Zimbabwean asylum-seekers. Next week's hearing in the Court of Appeal centres on a woman known only as HS – her identity is protected by an anonymity order. A doctor, she faces removal even though her brother has been allowed to settle in the UK because of his involvement with the opposition MDC.
Sarah Harland, co-ordinator of the Zimbabwe Association in Britain, said: "I think the double standards are breathtaking. It would be insane to send people back at this time."
A government source said there were no "immediate" plans to enforce returns to Zimbabwe. A spokeswoman for the UK Border Agency said: "We have made clear our grave concerns about the appalling human rights situation in Zimbabwe, and continue to press for an end to abuses. We will continue to provide protection for any asylum-seekers that we or an independent judge deems in need of protection. That's a proud tradition in our country and we intend to honour it."