The need to ban extremist group Hizb-ut-Tahrir

David Cameron forced Gordon Brown onto the defensive during their first Prime Minister's Question Time confrontation in the Commons, when he asked why extremist group Hizb-ut-Tahrir has not been banned by the Government.

Although the Government agreed two years ago that a ban should be imposed, the new Prime Minister found himself on the back foot when the Conservative Leader demanded to know why that and not happened.

And Mr Brown surprised and dismayed some of his own MPs when he tried to hide behind the excuse that he has only been in his new job for five days.

During exchanges which concentrated on the security crisis facing the country in the wake of the latest bomb plot outrages, Mr Cameron urged the Government to speed up the review of the use of phone tap evidence in terrorist related court cases, then declared: "We need to act to address groups which are seeking to radicalise young people.

"Almost two years ago the Government said the extremist group Hizb-ut-Tahrir should be banned. We think it should be banned. Why has that not happened?"

Initially, Mr Brown sought to sidestep the question by announcing that his new Security Minister Lord West would review NHS recruitment following news that several of the weekend bomb plot suspects are doctors employed by the service.

But when Mr Cameron stepped up the pressure and demanded to know when Hizb-ut-Tahrir would be banned, "given that it is poisoning the minds of young people and has said that Jews should be killed wherever they are found", Mr Brown admitted that a prohibition order could have been imposed under prevention of terrorism legislation, but had not been. "We will look at this issue; but we need the evidence. We need to look at the details. We should approach this in a sustained and calm way without jumping to conclusions," he said.

Mr Cameron responded: "Two years have elapsed since the Government said there should be a ban. People simply won't understand why an organisation urging people to kill all Jews hasn't been banned. As well as preventing radicalisation and stopping future dangers, we need to protect ourselves from present dangers."