The Home Office has published the Terrorism Bill amid confusion over whether it is prepared to compromise on the plans.

The anti-terror proposals include a provision on giving the police power to detain suspects for up to three months without charge.

They also seek to prohibit acts preparatory to terrorism such as training, glorification and incitement of terrorist acts and extremist literature and bookshops.

Charles Clarke said on Wednesday that the government was adopting stringent measures in response to the threat posed by July's London bombings.

"The terrorist threat facing the UK is real and significant, and the government is determined to do all it can to protect our citizens from groups who would try to destroy our society, our way of life and our freedoms," he said.

"The recent terror attacks in London and elsewhere make it absolutely clear that we must adapt to be able to meet the changing nature of the terror threat facing us.

"It is vital that our law enforcement agencies have the tools they need to combat new and emerging terror threats, as the nature and tactics of terrorism evolves and changes.

"Clearly, we must strike a careful balance between the rights of individuals and the protection of society. But we are operating in an environment where we must do all we can to protect out way of life from those who would try to destroy it through violence and fear."

Concessions

But the prime minister and home secretary have differed on the extent to which they are prepared to make concessions to opposition parties.

With the government's Commons majority cut to 66 and Labour lacking a majority in the Lords, the Bill is by no means guaranteed a safe passage through parliament.

At his monthly press conference on Tuesday, Tony Blair said that the police had made a "compelling case" for the power that had not yet been answered by critics.

Downing Street added that the public would not forgive ministers for putting compromise before security in the event of a future terror attack.

Number 10 also recirculated a police paper setting out the case for three months detention, while on Wednesday the Foreign Office published a research paper showing that other European Union countries can allow terror suspects to be held for years without being brought to trial.

However the home secretary has indicated he is open to compromise on plans to detain terrorist suspects without charge for up to three months.

Charles Clarke will be responsible for piloting the Bill through parliament, and has been at the forefront of attempts to secure a cross-party consensus with the Conservatives and Liberal Democrats.

Flexibility

Clarke told MPs on Tuesday he was "genuinely interested in getting to an agreed position on this" and pledged to look at any suggestions "flexibly".

He has already watered down his plan to make "glorification" of terrorism a criminal offence.

Conservative leader Michael Howard said he was "yet to be persuaded" of the case for holding suspects for three months.

"I suspect that a much better approach would be to look at some of the other aspects of our judicial system," he told the BBC.

"Just extending the period to three months is perhaps too simplistic and not the most effective way of dealing with this problem."

And Liberal Democrat spokesman Mark Oaten conceded the issue was a "sticking point".

Speaking on Wednesday the prime minister's official spokesman indicated that consensus could be achieved by the opposition parties backing down or offering better alternatives.

"Of course we want to proceed on the basis of consensus, but that is up to others," he said.

"And the key thing is whether people can address the real need as outlined by the police."