The UK is free to pursue independent trade policies for the first time in more than four decades after the Brexit transition period with the European Union came to an end.
Membership of the single market and customs expired at 11pm – four and a half years after the in-out referendum which sought to settle the issue but sparked political turmoil.
Prime Minister Boris Johnson said the EU had provided the UK with a “safe European home” during the 1970s, but the country has now “changed out of all recognition” with global perspectives.
His Christmas Eve deal with Brussels, which comes into effect immediately, allows for the continuation of tariff-free trade with the EU single market – though businesses and individuals will have to follow new rules.
The UK has reached several agreements with non-EU countries – such as Japan – to ensure continuity of trading arrangements for British companies from January 1.
Mr Johnson, writing in the Daily Telegraph, said the “great new deal” honoured the “most basic promises” of the 2016 referendum, and added that the UK has “taken back control of our money, our laws and our waters”.
“And yet it is also the essence of this treaty that it provides certainty for UK business and industry, because it means that we can continue to trade freely – with zero tariffs and zero quotas – with the EU.”
Under the new arrangements, freedom of movement rights will end, and while UK citizens will still be able to travel for work or pleasure, there will be different rules.
Passports must be valid for more than six months, visas or permits may be needed for long stays, pets will need a health certificate and drivers will need extra documents.
The automatic right to live and work in the EU also ceases, and the UK will no longer take part in the Erasmus student exchange programme.
Hauliers will face new rules, and lorry drivers heading for the Port of Dover will have to ensure they have a Kent Access Permit before entering the county on their way to the border.
Travel to Ireland will not change, but the Northern Ireland Protocol governing trade between Great Britain and the region entered into effect at 11pm.
It means Northern Ireland will remain in the EU single market for goods, and will apply EU customs rules at its ports, even though the region is still part of the UK customs territory.
The protocol will also see Northern Ireland follow certain EU rules on state aid and VAT on goods.
Gibraltar, whose sovereignty is disputed by Spain and Britain, will remain subject to the rules of the free-travel Schengen area, keeping the border with Spain open.
Government officials insisted the necessary border systems and infrastructure in the UK are in place, and they are ready for the “new start”.
Big Ben chimed at 11pm, but celebrations were muted by the coronavirus pandemic. The Prime Minister is understood to have marked the occasion with his family in Downing Street.
Eurosceptic MPs, once derided as fringe eccentrics on the margins of the Conservative Party, expressed their delight that the UK was finally leaving the customs union and single market.
Sir Bill Cash said it was a “victory for democracy and sovereignty” that could only be compared in peacetime with the evolution of modern democracy after the end of the Stuart dynasty.
Sir John Redwood expressed his “relief” that the UK had stated its wish to be “self-governing”, saying he looked forward to using the “new freedoms and opportunities now open to global Britain”.
Peter Bone, who planned to celebrate with French champagne to “show that we are pro-Europe but anti-EU”, said Eurosceptics had gone from being viewed as “strange” to getting the “support of people to defeat the establishment”.
Mark Francois, chairman of the European Research Group of Tory Brexiteers, said that waving goodbye to 2020 and the EU was a “marvellous example of a buy one, get one free”.
Former Ukip leader Nigel Farage, who played a key role in the 2016 referendum, said December 31 is a “moment to celebrate 2021 as an independent United Kingdom”.
He told the PA news agency: “It’s a big moment in our national story and the end of a very long road for tens of thousands of us who fought against the establishment.
“We celebrated on 31 January when we left the European Union – tonight we leave the single market and the customs union.
“Yes, we spare a thought for Northern Ireland and our fishermen, but this is a moment to celebrate 2021 as an independent United Kingdom. It’s a shame the pubs aren’t open.”
The UK’s chief negotiation Lord Frost said the UK has a “great future before us” with the chance to “build a better country for us all”.
But Scottish First Minister Nicola Sturgeon, a vocal critic of Brexit, said: “Scotland will be back soon, Europe. Keep the light on.”
Mr Johnson’s Brexit trade deal was overwhelmingly backed by MPs and peers as it cleared Parliament on Wednesday before receiving royal assent.
Labour supported the deal, despite misgivings from some pro-European MPs, but all the other opposition parties opposed the agreement, including the Brexit-backing DUP.
Additional Reporting By The Press Association