POLLS have opened as voters decide whether Theresa May's gamble of calling a snap General Election will pay off, or if Jeremy Corbyn's campaign has 'changed the face of British politics'.

At the end of one of the strangest General Election campaigns of modern times, Mrs May issued a last-minute plea to non-Tory voters to lend her their support to lead the Brexit negotiations which will define the country for generations.

Jeremy Corbyn, her rival in the race to Number 10, used his final rally speech to claim his campaign had "changed the face of British politics" and Labour was preparing for government.

The election period saw two acts of horrific brutality disrupt the democratic process, with the Manchester Arena bombing and the London Bridge rampage changing the complexion of the campaign.

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People will go to their polling stations amid heightened security as a result of the terror threat but Labour leader Mr Corbyn said voting on Thursday was a way to "honour the victims of these atrocities" by "showing democracy that will never be cowed by terror".

Before the terrorist attacks, Mrs May's campaign had suffered a setback of her own making - with an unprecedented U-turn on a key manifesto policy.

The unexpected proposal to scrap a planned cap on social care costs changed the momentum of the campaign, as a lmost immediately the polls began to tighten, while Tory candidates found anxious voters raising the issue of what the opposition parties quickly dubbed the "dementia tax" on the doorstep.

Within days the Prime Minister had performed a U-turn, announcing that they would consult on a cap in a green paper after the election - effectively rewriting a central plank of the manifesto mid-campaign.

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Despite the setback Mrs May continued trying to fight the campaign on her chosen battleground of Brexit, using a final message to voters to urge them to back her ahead of the negotiations with Brussels.

She said: " If we get Brexit right, we can build a Britain that is more prosperous and more secure. A Britain in which prosperity and opportunity is shared by all. A Britain where it's not where you come from or who your parents are that matter, but the talent you have and how hard you are prepared to work. The greatest meritocracy in the world."

In a message directly aimed at wavering voters who may lean towards other parties, she added: "I can only build that better country and get the right deal in Brussels with the support of the British people. So whoever you have voted for in the past, if that is the future you want then vote Conservative today and we can all go forward together."

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The Labour leader, who claims to have addressed more than 100,000 people at campaign events, used a speech at his final rally in his north London stronghold to claim he had reshaped British politics.

He said: "As we prepare for government, we have already changed the debate and given people hope. Hope that it doesn't have to be like this; that inequality can be tackled; that austerity can be ended; that you can stand up to the elites and the cynics.

"This is the new centre ground. The place where most people actually are. The policies the majority actually want, not what the establishment and its media mouthpieces insist they should want. This is the new mainstream, and we have staked it out and made it our own - together."

Liberal Democrat leader Tim Farron urged Labour supporters to vote tactically to keep out the Conservatives.

He said: "We will stand up for you on Europe, on schools and hospitals and to stop the heartless dementia tax. So stand up and make your vote count for the Liberal Democrats today."

The opinion polls continue to suggest a Tory lead, although the scale of the advantage in recent studies has ranged from a single point to a double-digit cushion for Mrs May.

Mr Corbyn's best hope may be a high turnout among young voters, especially in target seats.

The weather is unlikely to prove too much of a deterrent to voters, although rain is forecast to move north through the UK during the course of the day.

Election expert professor John Curtice, of Strathclyde University, said unless there was a major storm which disrupted transport links, turnout was unlikely to be affected: "We live in a country where a bit of drizzle is commonplace."