Nigel Farage has claimed victory in the EU referendum for the Leave campaign, saying 23 June would "go down in our history as our independence day".
The UKIP leader told supporters at a Brexit party: "Dare to dream that the dawn is breaking on an independent United Kingdom."
With 335 out of 382 results declared, the BBC has forecast a Leave win.
The English shires and Wales voted for Brexit while London, Scotland and Northern Ireland backed a Remain vote.
Mr Farage, who has built his political career on campaigning for the UK to leave the EU, had predicted at the start of the night that Remain would "edge" a win, a view which he said was based on some "big polling" done by "the financial markets".
But by 03:45 BST, he returned to a Brexit party in London and told supporters: "This, if the predictions now are right, this will be a victory for real people, a victory for ordinary people, a victory for decent people.
"We have fought against the multinationals, we have fought against the big merchant banks, we have fought against big politics, we have fought against lies, corruption and deceit.
"And today honesty, decency and belief in nation, I think now is going to win.
"And we will have done it without having to fight, without a single bullet being fired, we'd have done it by damned hard work on the ground."
Earlier Mr Farage, who was not part of the official Vote Leave campaign, said Eurosceptics had long been dismissed as "fringey" and "fruitcakes" but now: "The Eurosceptic genie is out of the bottle and will not be put back".
Speaking at a Leave.EU party in central London, he suggested that a late decision to extend the voter registration deadline by 48 hours - after a computer glitch left some people unable to sign up in the final two hours before the original deadline - might play a part in a Remain win.
It later emerged that more than 430,000 people applied to register to vote during the extension - the bulk of which were aged under 45.
But UKIP's sole MP, Douglas Carswell, appeared to disagree with his party leader.
He said the Leave campaign could "legitimately complain about taxpayer-funded propaganda" by the pro-Remain government but "when it comes to getting people to engage in a referendum, surely that's a good thing".