General Election campaigning was returning at full throttle on Monday amid an escalating war of words over terrorism in the wake of the London Bridge attack.
Labour leader Jeremy Corbyn used a speech on Sunday evening to turn his fire on Theresa May, accusing her of denying police and security services the resources they need while suppressing evidence of Saudi support for violent extremists.
Conservatives hit back with a broadside on Mr Corbyn's record of opposing counter-terror laws and the use of shoot-to-kill tactics by police facing armed attackers.
In a high-profile speech after chairing a meeting of the Government's Cobra emergency committee, Mrs May will seek to return the campaign focus to her favoured issue of leadership.
She will say that the right leader is needed to deliver not only a strong economy and a successful Brexit, but also security at a time when the country faces a very serious terror threat.
Declaring that "enough is enough" after the third atrocity in as many months, Mrs May on Sunday set out a raft of proposals for action to improve security after the June 8 election.
These could include:
:: Longer jail sentences for terrorists and their accomplices.
:: New powers for police and security agencies.
:: Moves to counter radical propaganda and prevent the growth of segregated societies in the UK.
:: International agreement to stop extremists using the internet to spread their message and plan attacks.
Mrs May said that recent attacks in Westminster, Manchester and London Bridge represented a "new trend" of individuals and small groups inspired by the same "evil ideology of Islamist extremism" even when they are not part of a network together.
In a significant ramping up of her anti-terror message, the PM said: "It is time to say enough is enough.
"Everybody needs to go about their lives as they normally would. Our society should continue to function in accordance with our values.
"But when it comes to taking on extremism and terrorism, things need to change."
Labour criticised Mrs May for making a policy statement during a suspension of campaigning agreed by all the parties except Ukip.
And when the brief pause came to an end, Mr Corbyn told supporters in Carlisle that Conservatives had tried to "protect the public on the cheap", cutting 20,000 police officers despite warnings from the Police Federation that it would undermine safety.
The Labour leader, who has promised to recruit 10,000 police, said he would use his first day in office if he wins on Thursday to commission a report from security services on the terror threat.
He sought to end the earlier controversy over his support for shoot-to-kill, saying he backed the "full authority for the police to use whatever force is necessary to protect and save life as they did last night, as they did in Westminster in March".
Mr Corbyn said: "Our priority must be public safety and I will take whatever action is necessary and effective to protect the security of our people and our country."
But his comments were derided by Conservative security minister Ben Wallace, who said: "He has boasted about opposing every single counter-terror law, opposed the use of shoot-to-kill, and gave cover to the IRA when they bombed and shot our citizens.
"Voters will judge him on his views and actions in the last 30 years, not his desperate promises and evasive soundbites three days out from polling day."
Mr Corbyn was campaigning in the North East on Monday, as Labour tried to consolidate a clear shift in its favour in opinion polls which have seen one survey put the party within a single percentage point of overhauling the Tories.
Liberal Democrat leader Tim Farron and the Scottish National Party's Nicola Sturgeon were in Edinburgh to be grilled on live TV by a studio audience for BBC One's Question Time, postponed from Sunday due to the terror attack.