Two months on, these promises are looking at best increasingly rash and at worst doomed to fail in the face of opposition from human rights groups and costly legal battles with alleged extremists.
The Government has drawn up a list of at least 50 suspects it plans to boot out of the country, but Mr Clarke has yet to order police raids to begin. The only cleric who has been successfully dealt with is Omar Bakri Mohammed, founder of al-Muhajiroun, which is dedicated to the overthrow of Western society. When the preacher left Britain for a holiday in Lebanon, immigration officials banned him from returning.
Despite pressure on the Home Secretary to act, he is understood to be facing difficulties in finding suitable high-security cells for his targets, because jails are already overcrowded. Officials have warned that they do not want any alleged extremists held together.
Ministers are already facing stiff opposition to plans to deport 10 men picked up in raids ordered last month by Mr Clarke. Already subject to control orders, they were returned to custody after the London bombings. The detainees have appealed against deportation, and their lawyers are locked in a legal battle with the Home Office. If the case goes to the European Court of Human Rights, it could last three years and cost the taxpayer up to £5m.
The suspects include Abu Qatada, described as Osama bin Laden's spiritual ambassador to Europe, who would be returned to Jordan. However, Amnesty International has already denounced as worthless pledges by Jordan, which has been accused of widespread human rights abuses, that Abu Qatada will not be tortured if he is returned to the country. Amnesty has also criticised plans to send the remaining nine suspects back to Algeria, which has an equally poor human rights record.
Ministers had expected to face a further obstacle to their anti-terror measures in the form of new immigration rules drawn up by the EU. But when the new directive was published last week, it turned out to be restricted to illegal immigrants and asylum-seekers.
It does not prevent the deportation of undesirable foreign nationals who are living legally in a country, a climbdown by the EU that has led to calls from the Opposition for deportations to start immediately.