The Conservatives are attempting to shift the election battleground to the economy with an attack on Labour’s tax and spending plans.
The Tories claimed Labour’s spending plans to date amounted to a £45bn “bombshell”.
But Labour said its plans were fully costed and that the Tories’ calculation contained “huge” errors and was not “worth the paper it’s written on”.
Parliament has now been dissolved ahead of the 8 June general election.
It means every seat in the House of Commons has become vacant and there are no MPs until a new Parliament is elected. However, government ministers retain their roles and continue their work.
Mrs May is expected to be driven the short distance from 10 Downing Street to the Palace for a short audience with the Queen.
The parties have not yet released their election manifestos, but their taxation plans have already come under the spotlight, with Prime Minister Theresa May refusing to repeat her party’s 2015 “tax lock guarantee” – while promising there would be no increase in VAT.
The Tories have now turned their fire on Labour’s plans with an attack poster claiming the “bombshell” from Labour’s commitments to date, which they say “don’t stack up”.
Labour, which is promising to suspend the closure of hospital services across England, has already pledged to appoint an extra 10,000 police officers and increase in NHS workers’ pay, and it also plans to borrow to invest extra money in infrastructure.
The Conservatives have also included costings from other announcements, speeches and interviews made by party figures dating back to Jeremy Corbyn’s 2015 leadership campaign, as well as proposed revenue raisers such as Labour’s planned corporation tax increase.
Brexit Secretary David Davis said: “Jeremy Corbyn’s nonsensical and irresponsible ideas pose a grave risk to the future of Britain’s economy and the finances of every family in the country.
“His many, ill-thought through promises simply don’t stack up and could not be paid for.”
On Sunday Mrs May said she had “absolutely no plans” to increase taxes, and that a Conservative government would not raise VAT if she won the general election.
But she did not back predecessor David Cameron’s pledge which also ruled out rises in income tax and National Insurance until 2020.
Labour has also said it will not raise VAT, and has promised low taxes for what it calls “low and medium earners”.
It has also said it will increase corporation tax and reverse capital gains and inheritance tax cuts.
The party’s campaign manager Andrew Gwynne said the Tory “bombshell” dossier was “yet more nonsense from a Tory campaign that’s all slogan and no substance”.
Labour said more than £2bn in pledges that that were not current party policy had been included in the Tories’ calculations, as had others that were fully-funded.
“Their claims are so flimsy that even the most cursory reading reveals error after error, with claims that don’t add up, things they say are Labour policy which aren’t and blatant misrepresentation of policies which we have clearly set out how to pay for,” Mr Gwynne added.
Labour plans to return to the NHS with its campaign on Wednesday, promising to suspend local reform plans involving closures to A&E, maternity and stroke units.
It said the process was causing confusion and risked being driven by money rather than what was best for patients.
But the Conservatives dismissed the idea and said funding was in place to pay for the changes.