Jeremy Corbyn has been accused of a “totally inappropriate and crassly timed” intervention as he seeks to draw links between Britain’s involvement in military interventions overseas and terrorism at home, as the General Election campaign resumes four days after the Manchester bomb attack.

The Labour leader’s speech comes as a brace of polls suggest the Conservative lead over his party is narrowing, with one showing Theresa May’s Tories just five points ahead – the tightest since the campaign for the June 8 election was launched.

All the major parties are expected to resume national campaigning on Friday, although Prime Minister Mrs May will not be involved as she is in Italy for a summit of the G7 group of industrialised nations.

In a speech in London, Mr Corbyn will launch a barely veiled attack on the Conservative record on terror, saying it is the “responsibility” of governments to minimise the risk of attacks by giving police the funding they need and ensuring their foreign policy does not heighten the threat to the UK.

But Security Minister Ben Wallace condemned Mr Corbyn’s speech and said Islamist terror was aimed at the British way of life rather than a response to foreign military interventions.

Speaking on Radio 4, shadow international trade secretary Barry Gardiner added that British foreign policy is an “excuse” used by terrorists to justify their attacks.

He highlighted the conflicts in Iraq, Libya and Syria as he criticised military interventions that have “gone in hard but then has really lost its way”.

“Absolutely clearly, the responsibility for these atrocities that have taken place is with those that have perpetrated them. But what we have to understand is that they use these things as an excuse and there are young people – young men usually, but not exclusively – who are alienated from our society.”

Lib Dem leader Tim Farron said: “A few days ago, a young man built a bomb, walked into a pop concert and deliberately slaughtered children. Our children. Families are grieving. A community is in shock.

“Jeremy Corbyn has chosen to use that grotesque act to make a political point. I don’t agree with what he says, but I disagree even more that now is the time to say it. That’s not leadership, it’s putting politics before people at a time of tragedy.”