The ban on deporting asylum-seekers back to Darfur has been lifted by the Government despite warnings of widespread murder and torture of dissidents in the Sudanese region.

One Darfuri has already been sent back to Sudan and another man, Abubaker Yousef Mohamad, will be returned next Sunday, The Independent has learnt. He is alleged to have been detained for two months and beaten the last time he was deported. Other Darfuri asylum-seekers have been told to expect deportation.

Ministers stand accused of hypocrisy for resuming the expulsion of Darfuris just 10 months after Gordon Brown called the region one of the world's "darkest corners", adding that "human rights are universal".

Download the new Independent Premium app Sharing the full story, not just the headlines

They were warned that asylum-seekers put on flights back to the Sudanese capital, Khartoum, would become targets for the police and security services. The UN High Commissioner for Refugees has argued against the return of Darfuris to Khartoum, saying they face torture or death.

Deportations of Darfuris to Sudan were halted last year while the Home Office fought a legal battle with protest groups opposed to removals. It promised removals would be put on hold while it reviewed fresh evidence of ill-treatment faced by Darfuris at the hands of Sudanese authorities.

The Home Office has confirmed it had authorised the resumption of removals of Darfuri refugees.

Campaigners and two Lib Dem frontbenchers will today write to the Home Secretary Jacqui Smith, calling for the deportations to be put on hold. They said attacks by the rebel Justice and Equality Movement (JEM) near Khartoum two months ago made all Darfuris living in the capital vulnerable to persecution.

Mr Mohamad, a JEM activist, 33, was arrested six weeks ago in London as he travelled to a meeting with his solicitors. He was sent to Oakington immigration removal centre, Cambridgeshire. He will be deported on 13 July.

He fled from Darfur to Turkey in 2003 after a raid on his village during which his brother had been killed and his wife had vanished. But he was sent back to Sudan and arrested on his return to Khartoum. During two months' custody he says he was beaten with gun butts, metal rods and hoses. A guard helped him escape and he travelled to Libya, France and then Britain.

His supporters argue that he would be a particular target for the Sudanese authorities because of his political activism and his previous prison escape.

Speaking through an interpreter he told The Independent: "Any Darfuri is at risk if they are returned to Sudan. The authorities can differentiate between Darfuris and people from other parts of Sudan. They know exactly who I am. Britain was one of the leading countries to talk about the suffering of Darfur. I am very disappointed."

Louise Roland-Gosselin, director of the Waging Peace campaign group, said: "We're deeply concerned at the British Government resuming its policy of returning Darfuri refugees to Khartoum, especially given the known arrests, torture and killings in the city."

Donna Covey, the Refugee Council's chief executive, said: "We are horrified these deportations have resumed. It is inexplicable that the Prime Minister can take a lead in trying to solve the tragedy of Darfur, but one of his Government departments is removing those who have fled the genocide."

In a letter to the Home Secretary, the Liberal Democrats' home affairs spokesman, Chris Huhne, and its foreign affairs spokes- man, Ed Davey, today call for the Home Office to halt all moves to deport Zimbabwean asylum-seekers. They are concerned over the "discrepancy between the Government's criticism of Mugabe's brutal regime and the treatment of Zimbabweans in this country".

A Home Office spokes-man commented: "Our asylum decisions are humane and compassionate, and oversight by independent judges helps ensure justice is done ... but we do not believe everyone is in need of international protection."