There have calls for the restoration of control orders in the wake of the London Bridge terror attack - which would see terror suspects placed under curfew and banned from using the internet.
Prime Minister Theresa May has promised to review the UK's counter-terrorism strategy, with the prospect of enhanced powers for police and security services and tougher jail sentences for extremists.
Speaking outside 10 Downing Street, she promised to ensure that police and security services have "all the powers they need" to tackle a "more complex, more fragmented and more hidden" threat.
And she indicated that courts could be given powers to impose harsher punishments not only on the terrorists themselves but also those guilty of "apparently less serious" offences.
But there was no immediate guidance on specific measures that may be put forward after the General Election if the PM retains power.
The former independent reviewer of terrorism legislation, Lord Carlile of Berriew, predicted that the first item on the agenda in any review would be the reintroduction - possibly under a new name - of control orders, which were replaced by the less stringent Terrorism Prevention and Investigation Measures in 2011.
Introduced by Tony Blair in 2005, the orders - which allowed suspects to be relocated away from their home communities, subjected to 16-hour home-arrest curfews and barred from using mobile phones or the internet - had won the support of the courts and "may have saved a lot of lives", said the crossbench peer.
They were more widely used than the time-limited Tpims brought in by the coalition, which exclude suspects from going to specific places and require them to wear electronic tags and report regularly to the police, but allow them to use mobiles and the internet and to apply to the courts to be able to stay away from home.
Firm proposals for Mrs May's review are expected to be drawn up over the coming period, taking account of the changing nature of the threat displayed at Westminster, Manchester and London Bridge.
The three attacks are not thought to have been directly connected in their preparation, but to have been committed by individuals and small groups inspired by similar ideas.
Foreign Secretary Boris Johnson hinted at the kinds of misdemeanour that could be subject to tougher sentencing, sending a message "to those who sympathise or encourage or harbour or aid or abet these killers in any way ... Your time is up. The wells of tolerance are running empty. We will not let you disrupt our lives or our democracy."
There were few clues in the Conservative manifesto about any new powers which may be offered to the police or security agencies.
The document stated that a Tory government would "continue to invest in our world-leading security services and maintain and develop our counter-terrorism strategy to protect us from terrorism at home and abroad" but went into little detail beyond the establishment of a Commission for Countering Extremism.
A Counter-Extremism Bill announced in last year's Queen's Speech ran into the sand after criticism of its proposals for a new regime of Banning Orders for organisations and individuals who "preach hate" without breaching existing laws.
It was unclear whether these ideas would be revived as part of the new review.
Lord Carlile said that internment of suspected extremists was "not a realistic option", as it would be ruled unlawful by the courts.
And he said that there was "no evidence" to support any extension to the 14-day period for which terror suspects can be held without trial, which would be a "purely symbolic" measure.
He backed longer maximum sentences for offences like incitement of terror, conspiracy or "providing bed and board" to plotters.
But he warned against mandatory minimum sentences, which could induce juries to acquit rather than trigger a penalty which they regard as excessive.
Lord Carlile called for the budget for the Government's Prevent counter-radicalisation programme to be "at least doubled", arguing that its benefits have been shown to outweigh concerns from some community leaders that it has alienated British Muslims.