Disclosing this on Sunday, British Home Secretary David Blunkett said the new measures, to be introduced only if Prime Minister Tony Blair's Labour government is re-elected next year, would allow evidence gained from telephone tapping to be used in trials.
Blunkett said people who had not committed an offence but were suspected of planning terrorism acts could have their actions restricted by so-called civil orders, similar to a system of anti-social behaviour orders introduced recently to target repeat offenders.
The proposals will most likely alarm civil liberties campaigners.
Blunkett, interviewed by the ITV television channel, said special terrorism trials with judges sitting alone were being considered.
The United Kingdom, as a close ally of the United States both in Iraq and in the "war on terrorism", is bracing itself for possible attack by groups such as al-Qaida.
A top British policeman said earlier this year that an attack was more a matter of when, rather than if.