Video report by ITV News Political Correspondent Paul Brand
Boris Johnson and Jeremy Corbyn have used what could be their final Prime Minister's Questions to kick start their general election campaigns.
Also on Wednesday, legislation needed for an early election to take place cleared the House of Lords and will now go forward for Royal Assent to become law.
The prime minister used the opportunity to tell MPs there is a "stark choice" between voters choosing "economic catastrophe" with Labour or "getting Brexit done" with the Tories.
Mr Corbyn opted to talk about anything but Brexit in an attempt to change the tune of the forthcoming election campaign and instead made a majority of exchanges about the NHS.
He claimed under the Tories the NHS is "up for grabs" to US corporations in a "Trump-style trade deal".
Mr Johnson insisted this wasn't the case, claiming if he wins the election he will "invest massively in that NHS and take it forward with the funds that we will make available from a strong and growing economy".
He says he is prepared for a “tough” general election battle after MPs cleared the way for the first December poll in almost a century.
Talks on potential deals to give candidates a clear run are already underway at a local level, says ITV News Political Correspondent Libby Wiener
But Labour and the Liberal Democrats appear, at least outwardly, to be much more optimistic about their chances of victory, with shadow chancellor John McDonnell saying "we'll have a majority".
Mr McDonnell claimed Prime Minister Johnson is "worried" about fighting the election and said having 500,000 members "already knocking on doors" means his party can "win the argument and we'll win a Labour government".
He said if there is a hung Parliament, "what we'd do is we'd form a minority Labour government".
But leader Corbyn rubbished any suggestion Labour would form "no electoral pacts" ahead of the poll, saying "we're fighting this election to win it".
But Liberal Democrats leader Jo Swinson said her party had already began negotiating with other parties that wanted to stop Brexit.
"We are obviously are - as has been discussed - in negotiations with the United Remain initiative so there may well be a small number of seats where there are arrangements that are agreed," she said.
"So we will of course work with other parties that also want to stop Brexit. We have been doing that successfully in the House of Commons."
Despite claiming it will be a difficult election to win, Prime Minister Johnson is clearly confident his party can gain a majority and on Wednesday morning he tweeted a video, writing "let's take our country forward".
At PMQs Mr Corbyn repeatedly berated Mr Johnson over the Tories' record on the NHS and accused the prime minister of planning to trade parts of the health service with the US after Brexit.
He claimed that while "the Government is having secret meetings with US corporations" patients in the UK "continue to suffer".
Mr Johnson replied: "Are you seriously suggesting that the NHS should not engage in negotiations to ensure British patients get the drugs they deserve?
"Are you so phobic of American companies that you will forbid them from having these discussions?"
Mr Corbyn, in his concluding remarks, said: "People have a chance to vote for real change after years of Conservative and Lib Dem cuts, privatisation and tax handouts for the richest, this Government that has put our NHS into crisis.
"This election is a once-in-a-generation chance to end privatisation in our NHS, give it the funding it needs and give it the doctors, the nurses, the GPs and all the other staff that it needs."
Mr Johnson tried to return the argument to being about Brexit and suggested the Labour leader had a lack of leadership that meant he could not deliver.
"Leadership means standing up for the people of this country, standing up for our police, standing up for our NHS, making sure it gets the funding that it needs and standing up for our economy and wealth creators," he said.
"Above all it means getting Brexit done and ending the dither and delay.
"The time for protest is over, it's time for leadership - and that is what this Government provides."
The Lib Dems also go into the election confident their pro-Remain stance will see them pick up support with leader Jo Swinson pitching herself as “the Liberal Democrat candidate for prime minister”.
“It is our best chance to elect a government to stop Brexit,” she said.
For the SNP, Scotland’s First Minister Nicola Sturgeon said it was an opportunity for Scotland to put an independence referendum back on the agenda.
“A win for the SNP will be an unequivocal and irresistible demand for Scotland’s right to choose our own future,” she said.
"Independence is important, having the right to choose our own future is vital so that we never again find ourselves in the position in Scotland of having a future direction imposed upon us."
She said the SNP would not be part of any "formal coalitions" but said she implied the party could help Labour by saying she "would never, ever put the Tories in government".
Mr Johnson finally got his wish of an election thanks to the one-page Early Parliamentary Election Bill, which enabled the election to be held on December 12.
Following his Commons victory on Tuesday – at the fourth time of asking – the prime minister sought to rally Tory MPs by telling them it was time to “get Brexit done”.
Also on Wednesday, legislation to trigger a pre-Christmas general election headed for the statute book after clearing the House of Lords.
The unamended one-page Bill, which has already been passed by the Commons, was given an unopposed third reading by peers.
The legislation will now go forward for royal assent enabling Parliament to be dissolved on November 6, paving the way for an election on December 12.
The prime minister is aiming to restore the Tories’ Commons majority lost by Theresa May in 2107 so he can finally end three years of deadlock and get his Brexit deal through Parliament.
However, there are risks in going to the country having failed to deliver on his promise to deliver Brexit by October 31 “do or die” and with Nigel Farage’s Brexit Party denouncing his deal with Brussels.