He said: 'If we did use it, millions are going to die.
That would have uncertain consequences for Britain's US$2.5 trillion ($3.5t) economy, and future government policy on everything from government spending and corporate taxation to bond issuance.
He said: 'I would do everything I can to ensure that any threat is actually dealt with earlier on by negotiations and by talks, so that we do adhere to our obligations under the nuclear non-proliferation treaty.
The Ipsos MORI poll put the Conservatives on 45%, down four points from a comparable survey on 18 May, with Labour up 6 points to 40 percent.More news: Scott wields veto pen on new budget
But if she fails to beat the 12-seat majority her predecessor David Cameron won in 2015, her electoral gamble will have failed and her authority will be seriously undermined.
"Under the Conservatives, the richest have got richer, while most people's incomes have fallen or stagnated".
Criticising Mrs May's record, he said: "You can not protect the public on the cheap".
The findings echo other recent polls which show May's once commanding lead of more than 20 points when she called the campaign being whittled away, meaning she might no longer win the landslide she hoped.
But she was accused by one audience member having "called an election for the good of the Conservative Party, and it's going to backfire on you". Although the political consensus is that she will be returned to office with a larger majority, Mrs May's reputation has not been enhanced by an edgy and defensive campaign.
"I had the balls to call an election".More news: Djokovic, Nadal reach French Open third round
With the pollsters all testing so many variables and adjustments in this election, it is not surprising that there is a huge range of forecasts, Lauderdale said."As far as I can tell, the major differences I am seeing are not down to the raw data that the different pollsters are getting", he said.
Mr Corbyn was pressed by the audience over whether he would pursue a coalition deal with the SNP in the event of a hung parliament and the Labour leader insisted there would be "no deals". On Wednesday she sent a senior minister to a TV discussion with six other party leaders.
On Friday, YouGov said its model suggested the Conservatives were on course to win 313 seats, 13 seats short of a majority.
However, if the latest polls are wrong - and they have previously underestimated Conservative support - and May wins a sizeable victory, she will ax current finance minister Philip Hammond and replace him with interior minister Amber Rudd, the Daily Telegraph reported.
But Chancellor Philip Hammond warned that Labour would destroy jobs by raising taxes and increasing borrowing.
Blistering questions from a studio audience put Theresa May and Jeremy Corbyn under pressure on their weak spots of social care and defence.More news: MTV will livestream Sunday's Manchester benefit concert
When I became Prime Minister, I promised that I would be driven by the interests of ordinary working families and not for the benefi t of the privileged few.