MPs agreed today to ban a Somali extremist group after ministers alleged they had links to al Qaida.

Policing Minister David Hanson said Al Shabaab had carried out a string of attacks in the Horn of Africa and had pledged support to Osama Bin Laden's organisation.

The decision to add them to the list of proscribed organisations will prevent Al Shabaab campaigning or raising funds in the UK and ban people from joining the group.

Mr Hanson told the Commons: "The group has waged a violent campaign against the Somali transitional federal government, and has undertaken a violent campaign against the African Union peace troops in Somalia since the beginning of 2007.

"It has undertaken a range of terrorist tactics such as suicide operations and roadside bombings."

The group carried out a car bomb attack in June 2009 which killed the Somali security minister and 30 other people, Mr Hanson said.

It was also behind co-ordinated suicide attacks on buildings including the Ethiopian embassy and UN development programme compound in the African country.

Mr Hanson added: "In September of last year Al Shabaab released a video in which they pledged their allegiance to Osama Bin Laden and as late as February 2, 2010 they have announced their intention to combine the jihad in the Horn of Africa with the global jihad led by al Qaida."

But Mr Hanson was challenged about the organisation's activities in the UK and MPs expressed concern that they were being asked to make the decision without being given access to secret intelligence material.

Labour's Dari Taylor (Stockton S), a member of the Intelligence and Security Committee, said unless evidence could be tabled "some in our community, with justice, will have concerns that the Government is exaggerating the existence of terrorism in Great Britain today.

"I would say that is the last thing that we would ever, ever want to countenance."

Mr Hanson said together with Home Secretary Alan Johnson he had decided that the group's activities were "evidence internationally of the intentions of this organisation".

He added: "I can't comment on security matters in this country in detail but we have made the assessment based on our assessment of that information as to whether or not this organisation should be proscribed."

Labour's Keith Vaz, chairman of the Home Affairs Select Committee, said a previous order banning Tamil separatist group the LTTE had caused wider difficulty for the Tamil community in the UK.

Mr Hanson said the order would not affect the Somali community in the UK.

But Mr Vaz said: "Despite your assurances, as soon as the order is passed it has a draconian effect on communities unconnected with this particular organisation."

MPs approved the order adding Al Shabaab to the list banned under the Terrorism Act 2000 without a vote.

The order will need to be approved by the Lords before coming into force.