Meanwhile Foreign Secretary Boris Johnson also hit out against Mr Corbyn, saying he “hasn’t got a clue” when it comes to Brexit and that EU negotiators would “have him for breakfast”.
The attack came after four opinion polls for the Sunday newspapers put Labour between 35 per cent and 33 per cent, up significantly on the scores as low as 26 per cent it was recording early in the campaign.
General Election polls and projections: May 21
The Tory advantage was narrowed to just nine points in one survey by YouGov for the Sunday Times – the first time it has been in single figures in a mainstream poll since Theresa May called the snap election on April 18 – prompting talk of a “wobble weekend” for the Conservatives.
In an interview with Sky News’s Sophy Ridge On Sunday Mr Corbyn – who attended rallies and protests organised by the Republican-backed Troops Out Movement in the 1980s – said he condemned “all bombing” but had been trying to open up a peace process.
His comments were angrily denounced by Security Minister Ben Wallace who said voters would be “outraged” by his refusal to “unequivocally” condemn the IRA.
However ministers also found themselves forced onto the defensive over Conservative plans to overhaul funding of social care which would for the first time see thousands of elderly people required to pay for the cost of being looked after in their own homes.
Mr Corbyn’s defended his contacts with Republicans in the midst of the IRA bombing campaign.
He said: “In the 1980s Britain was looking for a military solution in Ireland. It clearly was never going to work. Ask anyone in the British Army at that time.
“Therefore you have to seek a peace process. You condemn the violence of those that laid bombs that killed large numbers of innocent people and I do.”
Pressed as to whether he would “condemn the IRA without equating it to …?” Mr Corbyn replied: “No, I think what you have to say is all bombing has to be condemned and you have to bring about a peace process.”
General Election round-up: May 20
Mr Wallace, who served as an Army officer in Northern Ireland, said: “People up and down the country will rightly be outraged that Jeremy Corbyn won’t unequivocally condemn the IRA for the bloodshed, bombs and brutal murders they inflicted on a generation of innocent people.
“Jeremy Corbyn has spent a lifetime siding with Britain’s enemies, but he and his extreme views could be leading our country and representing it abroad – negotiating with 27 EU countries – in just over two weeks’ time.”
Ministers said Labour’s recent poll boost would focus voters’ minds on the prospect that Mr Corbyn could be leading the Brexit talks, due to start less than two weeks after election day, underlining the nature of the choice facing them at the ballot box.
Meanwhile Mr Johnson told ITV’s Peston on Sunday: “We are at a critical phase in the history of this country. We have to get Brexit right. I am genuinely alarmed by the idea that it could be handled in just 11 days after the election by Jeremy Corbyn.”
The Foreign Secretary also defended the Conservatives’ plans to overhaul social care, saying that with the number of over 75s set to increase by two million over the next 10 years, they had to address the “huge costs” involved.
“I think it is a mark of Theresa May’s bravery and candour with the electorate that she is doing this. It shows the strength and purpose she will bring to everything she does if we are re-elected,” he said.