Theresa May launches strongest attack yet on Jeremy Corbyn amid concern her 'strong and stable' mantra lacks bite

Theresa May has accused Jeremy Corbyn of providing an "excuse for terrorism” in her strongest attack on the Labour leader to date.

The Prime Minister said Mr Corbyn had suggested the Manchester suicide bombing and other terrorist attacks “are our own fault” by linking terrorism to British foreign policy.

She also rounded on Mr Corbyn for the timing of his remarks - made in a campaign speech on Friday - just days after 22 children and adults were killed.

In an interview with the BBC's Andrew Neil, Mr Corbyn repeated his claim that terrorism was partly caused by "the consequences of our interventions in Afghanistan, in Iraq, in Libya".

The Labour leader also would not withdraw his previous description of NATO as a "Frankenstein" organisation, and refused six times to guarantee a replacement of Trident.

It came as senior Tories expressed concern that Mrs May’s message of “strong and stable” leadership is not cutting through with voters after one poll found her lead over Labour had been reduced to just five points.

Mrs May on Friday night claimed a victory in the war on terror as she convinced leaders of the G7 countries to sign up to plans she has drawn up for a crackdown on Facebook and other social media sites being used as recruiting tools by Isil.

She also struck a deal to make countries pick up British jihadis before they get home,  after it emerged that Manchester bomber Salman Abedi stopped in Germany on his way back from Libya just days before the attack.

Senior police officers claimed they had made "immense progress" in rounding up the bomber's network. However it was announced that armoured vehicles will patrol the streets this week amid fears of a Bank Holiday attack.

The scale of the terrorist threat facing Britain also became clearer as it emerged that the security services are carrying out investigations into 3,000 individuals and that another 20,000 have been classed as “subjects of interest” in the past.

Abedi had been a "former subject of interest" to MI5 who was "subject to review” before he carried out Monday’s suicide attack.

Mr Corbyn was criticised by figures from across the political spectrum for linking the Manchester attack to British foreign policy in Libya and elsewhere.

Boris Johnson, the Foreign Secretary, said his comments were “absolutely obscene”, while Andy Burnham, the new Labour Mayor of Manchester, said Mr Corbyn was wrong when he pointed to “the connections between wars our government has supported or fought in other countries and terrorism here at home”.

Mrs May looked angry as she addressed Mr Corbyn’s speech during a press conference at the G7 summit in Sicily.

She said: "I'm going to be very clear about what has been said today.

"What has happened is I have been here at the G7 working with other international leaders to fight terrorism.

"At the same time, Jeremy Corbyn has said that terror attacks in Britain are our own fault - and he has chosen to do that just a few days after one of the worst terrorist atrocities we have experienced in the United Kingdom.

"I want to make one thing very clear to Jeremy Corbyn, and it is that there can never be an excuse for terrorism, there can be no excuse for what happened in Manchester.

"The choice that people face at the general election has just become starker. It's a choice between me, working constantly to protect the national interest and to protect our security - and Jeremy Corbyn, who frankly isn't up to the job."

Mrs May will return to election campaigning over the weekend, desperate to reverse a trend which has seen her lead over Labour - once as high as 23 percentage points - steadily cut.

A YouGov survey for The Times, conducted on Wednesday and Thursday, after the terrorist attack, put the Conservatives down a point on the previous week on 43 per cent and Labour up three on 38 per cent.

The result would give the Tories a majority of between 20 and 30 MPs in the House of Commons, and Mrs May said it showed that every vote would count in June 8.

Conservative sources said the team around Mrs May was not panicking and would stick with the her “strong and stable” message.

The source said: “There is no panic as yet. They are genuinely not fussed by the poll. They are perplexed but they are not upset or frightened by the poll.”

However the insider added that aides were “slightly disappointed that her performance has not taken off.

“They were hoping there was going to be a ‘mother of the nation thing’, like Frau Merkel, John Howard. People would say ‘this is we want in her homely way’. That just has not happened.”

One Tory candidate said the party had been hit by a ‘double whammy’ from the manifesto, with supporters in the north of England upset about the cut to the winter fuel allowance, and those in the south worried about plans to force wealthy pensioners to pay more for social care.

He said it was “probably not a bad thing” that the poll showed how Labour could win the election, or run the Tories far closer than had been expected when the campaign started, adding: “There is still considerable mood of positivity out there.”

The candidate said: “No one is despairing but no one likes the polls.”

The Conservatives’ fightback will start on Saturday when Boris Johnson, the foreign secretary and a grassroots’ favourite, will tour the television and radio studios with the Tory message.

Mrs May will hope that her appearance on the first televised election debate on Monday will further boost her party’s prospects.

Mrs May and Mr Corbyn will be grilled for 45 minutes each by Jeremy Paxman, the former Newsnight interviewer with a reputation for tough questioning, and audience members.

There was a boost on Friday when the debate’s organisers Sky News and Channel 4 determined by a toss of a coin that Mrs May will answer questions after Mr Corbyn.

Historically going second in a televised debate is seen as an advantage because it will allow the Tory leader to make her points last and respond to those made by Mr Corbyn.

Ruth Davidson, the leader of the Scottish Conservatives who is close to Mrs May, said the poll “is going to focus minds on the idea that there could potentially be a Jeremy Corbyn prime ministership”.

She added: “If you don't want Jeremy Corbyn to be the prime minister of this country, if you don't believe he's equipped to be the prime minister of this country, there's no safe way to vote Labour.”