Politicians are making their final pitch for votes on the last day of campaigning before the EU referendum.
David Cameron, Jeremy Corbyn and Tim Farron are addressing rallies arguing the UK will be better off and safer with a Remain vote in Thursday's poll.
Boris Johnson and Nigel Farage are appealing to their own supporters - with the ex-London mayor urging people to "believe in our country".
More than 46 million people are eligible to vote in the referendum.
The UK public are being asked to choose whether the UK should stay in the European Union or leave in the first vote on the UK's links with Europe for more than 40 years.
It has been a campaign which BBC political editor Laura Kuenssberg says is too close to call, but which has changed British politics in a number of ways.
The four-month campaign comes to a close on Wednesday, with campaigners making a last-minute appeal to undecided voters, emphasising their main arguments and encouraging their supporters to turn out to vote.
Cameron, who has appeared alongside ex-PM Sir John Major and former Labour leader Harriet Harman in Bristol, has told the BBC that the decision will be irreversible and there will no coming back if the UK votes to leave.
"You can't jump out the aeroplane and then clamber back through the cockpit hatch," he told BBC Radio 4's Today.
Leaving the EU would be a "massive problem" for the UK, he said, doing "untold damage" to economic growth, jobs and family finances and hindering the opportunities and life chances of future generations.
"If I had to sum up this entire campaign in a word, it would be that word 'together'. I think together we are better able to face the challenges from terrorism and climate change, we are better able to grow our economies, better able to drive good trade deals... and I want us to get the good deals so we give better chances to everyone in our country."
Cameron said he "did not believe there were any risks from staying" in the EU, saying the eurozone was beginning to recover economically and this would have an effect on levels of migration into the UK after what he said was an "abnormal period".
He also said he would lobby for further changes to free movement rules in the light of European Court rulings if the UK votes to remain and said the process of EU reform will "continue on Friday", insisting that reducing net migration was "not an unrealistic ambition".
Characterising Leave supporters as "gravediggers of our prosperity", Sir John Major said leaving the EU was "no solution" to large-scale population movements around the world and may result in a "broken Britain with less importance and less influence in the world".
But Boris Johnson and other Leave campaigners said only a vote to leave the EU could give the UK the freedom it needs to set its own course, rejecting the economic forecasts suggesting the country would face a downturn following Brexit.
Speaking in Billingsgate fish market ahead of embarking on a whirlwind tour of England, the former mayor of London urged people to "believe in our country" and seize the moment.
"This is a crucial time, lots of people will be making up their minds, and I hope very much they will believe in our country, believe in what we can do," he said.
"It's time to have a totally new relationship with our friends and partners across the Channel. It's time to speak up for democracy, and hundreds of millions of people around Europe agree with us. It's time to break away from the failing and dysfunctional EU system.
"What you have seen over the last few years is a huge gulf opening up and widening between the incomes of FTSE 100 chieftains and people on the shop floor on low incomes who have basically seen either a pay freeze or in real terms their wages come down."