London, Oct 31 (PTI) The UK's main political parties kicked off their campaign for the December 12 General Election on Thursday, which was the deadline for Britain to leave the European Union (EU) until an extension was agreed till January 31, 2020.

British Prime Minister Boris Johnson was forced to abandon his "do or die" Brexit pledge for October 31 and instead focus on getting his bid for a snap election through the UK Parliament.

He enters the election battlefield with a lead over the Opposition Labour Party in pre-poll surveys and will hope the Conservative Party can win a majority mandate to be able to see his Brexit plan through Parliament.

"After three-and-half years, it was perfectly obvious to me that this Parliament is just not going to vote Brexit through. There are just too many people who are basically opposed to Brexit and want to frustrate it," Johnson said on the campaign trail at a hospital in Cambridge.

"If you vote for us and we get our programme through ... then we can be out at the absolute latest by January next year," he said, shifting his Brexit pledge timeline.

Labour Leader Jeremy Corbyn, who launched the party's campaign with a speech in south London, accused the ruling Tories of failing to live up to their promises and running a "corrupt system".

He said Labour would mount the "the biggest people-powered campaign in history" and go after the elite classes to transform Britain.

And in reference to Brexit, Corbyn said he wants to be elected Prime Minister to be able to "open negotiations with the EU about a sensible relationship with Europe".

"The Prime Minister [Johnson] wants you to believe that we're having this election because Brexit is being blocked by an establishment elite. People aren't fooled so easily. They know the Conservatives are the establishment elite," he said.

The anti-Brexit Liberal Democrats, meanwhile, have gone for an all-out stop Brexit message for voters, with leader Jo Swinson demanding a spot in the television debates traditionally taking place between the Conservative Party and Labour Party leaders.

"I don't think that the choice that we are being offered between Boris Johnson and Jeremy Corbyn is anywhere near good enough. Neither of those men are fit to lead our country," she said.

The Liberal Democrats now have 19 MPs out of the UK Parliament's 650, but their new election leaflet describes Swinson as "Britain's next Prime Minister" as the party hopes to capture a major swing in its favour.

It is also in talks with other smaller anti-Brexit parties, including the Green Party and the Welsh Plaid Cymru in an effort to combine forces against Brexit.

"Our polling shows that we are within a small swing of winning hundreds of seats, because the political landscape is so totally changed by what has happened in our country post-Brexit," said Swinson.

The campaign trail will get into full speed from next week once Parliament has been formally dissolved.

But all the major parties have already geared up for the major clashes ahead, expected to centre around Brexit, in the first December election in 96 years.

(This is an unedited and auto-generated story from Syndicated News feed, LatestLY Staff may not have modified or edited the content body)