Mr Clarke revealed that measures to introduce house arrest – which had been expected to apply immediately to the Belmarsh detainees – will be kept in reserve, and he made some concessions to his critics.
He said he had been advised that the powers were "valuable" but that the suspects did not need to be locked up once the current anti-terror legislation expires on March 14.
Lower grades of so-called "control orders" – such as travel bans and bars on access to phones and the Internet – will, however, go ahead straight away.
Renewing the existing laws allowing foreign suspects to be detained without charge or trial, introduced in the wake of September 11, was not "the way to go", Mr Clarke acknowledged, after it was declared draconian and disproportionate by the Law Lords in December.
To back up his controversial plans the Home Secretary last night released background papers saying plots uncovered amounted to clear evidence of a "real threat to British people and British interests" from terrorists affiliated to Al-Qaida, including Britons.
They also showed the independent watchdog appointed to oversee the Government's anti-terrorism laws advised Ministers to consider setting up special jury-less courts to conduct terrorism trials. But Mr Clarke did make some concessions designed to assuage critics and put political pressure back on the Tories and Lib Dems to back the Government's plan or appear weak on the issue.
If implemented, each house arrest order will be immediately referred to the High Court for an initial hearing within seven days.
If the court backs the Home Secretary's decision to impose the control order, there will be a full hearing at the High Court.
"The measures of judicial scrutiny which I propose should meet the genuine concerns which have been raised," he said.
But as the Home Secretary unveiled his Prevention of Terrorism Bill in the Commons yesterday, he faced staunch opposition from the Tories and Lib Dems, as well as a sizeable portion of his own backbench MPs.
They accused the Government of disregarding civil liberties and attacked it for deciding to push the Bill through both the Commons and Lords in a fort-
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night. It is expected to face a stormy passage in both houses. Labour backbencher Bob Marshall-Andrews declared it the greatest attack on the nation's liberty in three centuries.
Defending the Bill, Mr Clarke said: "This is an important Bill. It raised serious and difficult issues but we must have the capacity to protect our people now and in the future.
"It would be the gravest dereliction of duty to wait until we have suffered a terrorist outrage and then respond after the event."
The Tories and the Liberal Democrats last night took the rare step of tabling a joint amendment to try to halt the Bill, which is due to get its second reading in the Commons today.
Shadow Home Secretary David Davis, MP for Haltemprice and Howden, criticised the decision to fast-track the Bill.
"The Bill removes, for the first time in modern times, the presumption of innocence of the accused and it also removes the right of the accused to see the evidence and charges against them," he said.
"Further, the Government are introducing emergency measures that they say they will not need to use – why are these included in the Bill? Parliament needs more time to debate these issues.
"Our civil liberties and system of justice are worth more than two days of hurried decisions."
Liberal Democrat home affairs spokesman Mark Oaten said: "Charles Clarke's proposals are going to have a very rough ride through Parliament.
"It is wrong in principle, and dangerous in practice, to allow British citizens to be locked up in their homes on the say-so of a politician.
"Controls on suspects' movements and communications should only be made by a judge. "
Mr Clarke refused to bow to demands that house arrest control orders should be imposed by judges.
"I don't think that anybody else should have the responsibility for assessing national security issues that are at stake," he said.