In London yesterday, he announced plans to make it easier to exclude and expel people whose behavior is seen as likely to foment or provoke terrorism.
"Direct incitement to commit acts of violence is already a criminal offense. This proposal targets those who are not directly inciting [but who] glorify and condone terrorist acts, knowing full well that the effect on their listeners will be to encourage them to turn to terrorism," Clarke said.
Speaking in parliament, Clarke said the security authorities were drawing up a global database of extremists who would face automatic vetting before entry into Britain.
"The bill will deal with the giving and receiving of terrorist training. Our existing law already criminalizes much activity that could fall within this description, but we want to close the gaps to make sure that anyone who gives or receives training in terrorist techniques is covered," Clarke said.
There is much anger in Britain at the continuing presence here of radical Islamic preachers, like Jordanian-born Abu Qatada, often referred to as Osama bin Laden's ambassador in Europe.
Qatada has been under house arrest since 2002. But despite one judge's description of him as "a truly dangerous individual," Britain has been unable to expel the cleric because it is a signatory to the European Convention on Human Rights. British courts will not sanction deportations to countries that could impose the death penalty.
Another concern is Sheikh Omar Bakri Mohammed, labeled the "Tottenham ayatollah" by Britain's tabloid press after the district in London where he lives. Bakri is the former leader of the radical al-Muhajiroun group, whose website once praised the 9/11 hijackers as the "magnificent nineteen." He has lived in Britain for 20 years since his expulsion from Saudi Arabia. He blamed the London bombings on the British people because they had voted for Tony Blair. He was more circumspect yesterday.
"I declared publicly, I condemn all killings of any innocent people, in London and abroad. That [is what] I would like to hear: a condemnation [for] from the British government and that condemnation must be manifested in action with the withdrawal of forces from Iraq and Afghanistan," Bakri said.
Clarke said he is working now with countries like Jordan on gaining guarantees that deportees would not be tortured, mistreated, or executed.
Today, British Prime Minister Tony Blair is set to hold talks with police and security chiefs on what additional powers they need in the wake of the London bombings. Britain aims to have a new counterterror law in place by the end of this year.
But there is also a widespread perception here that the fight against Islamic extremism is not just about -- or even mainly about -- legislation and security measures. The key is engaging the multiple strands that make up the Muslim community in Britain.
Blair himself underscored this when he invited 25 mainstream Muslim leaders to talks at his Downing Street residence this week. These Muslim leaders have set up a taskforce to challenge the influence of extremist preachers and draw the community into mainstream British life.
But many grass-roots Muslim activists, such as Humera Khan of the An-Nisa Muslim women's group, say the people Blair is talking to are out of touch with young Muslims.
"I have no hope from this meeting he had with the Muslim leaders. The fact is if you look at the vast majority of the people he already spoke to, none of them have actually worked in the system [the community]. They don't understand how it works. The vast majority don't know what it feels like to really be engaged in society. They don't understand the mechanism. How then are they going to advise the prime minister on where's it's failing and what needs to be done?" Khan said.
On the grimy, crumbling streets of London's East End, home to one of the biggest Muslim communities in Britain, disaffection among young Muslims runs deep.
Many Muslim teenagers -- unemployed and with few qualifications -- nurse a deep sense of grievance against what they call worldwide persecution of Islam.
"You've got to understand, people won't just come and blow your country up for nothing. You declared war on them and of course they declared war on you. The whole family is wiped out and only a 10-year-old kid is left alive. What do you think that 10-year-old boy is going to do?" one Muslim teenager said. "Do you think he is going to come to your country and start shaking your hand? I don't think so. This is only the starting. I watched the TV the other day. They said there's about 2,000 suicide bombers, trained by Al-Qaeda. It's only a matter of time."
Time, clearly, is something no Western government has. The fear is that if British and other European societies fail to address the alienation of young Muslims, they will face even greater problems tomorrow.