Britain on Friday ends almost half a century of integration with Europe, finally making its historic departure from the EU to begin a new — but still uncertain — future, with emotions running high following years of wrangling and several false starts.

At the clocks strike 11:00 pm (4:30 am IST Saturday) —midnight in Brussels — Britain becomes the first country to leave the 28-member bloc and will go it alone for the first time since 1973.

Prime Minister Boris Johnson has backed Brexit since the 2016 referendum vote to leave that triggered deep bitterness and division but he has promised to unite the country in a new era of prosperity.

“Our job as the government, my job, is to bring this country together and take us forward,” Johnson said in a statement to mark the occasion. “This is not an end but a beginning. This is the moment when the dawn breaks and the curtain goes up on a new act.”

German Chancellor Angela Merkel called Britain’s departure a “sea-change” for the bloc, although nothing will immediately feel different because of an 11-month transition period negotiated as part of an EU-UK exit deal ratified this week. Britons will be able to work in and trade freely with EU nations until December 31, and vice versa, although the UK will no longer be represented in the bloc’s institutions. But legally, Britain is out —with no easy way back.

And while the exit terms have been agreed, Britain must still strike a deal on future relations with the EU, its largest trading partner, which sets out its negotiating position on Monday. “We want to have the best possible relationship with the UK, but it will never be as good as membership,” European Commission president Ursula von der Leyen said. “Our experience has taught us that strength does not lie in splendid isolation, but in our unique union.”

Getting this far has been a traumatic process.

Despite Britain’s resistance to many EU projects over the years — it refused to join the single currency or the Schengen free travel area — the 2016 vote to leave was a huge shock.

It unleashed political chaos in London, sparking years of bitter arguments that paralysed parliament and forced the resignations of two prime ministers. Johnson brought an end to the turmoil with his decisive election victory last month, which gave him the parliamentary majority to ratify the Brexit deal. But Britons remain as divided as they were nearly four years ago, when 52% voted to leave and 48% voted to remain in the EU.

Friday’s newspapers reflected that continued split, with best-selling eurosceptic tabloid The Sun triumphantly declaring “our time has come” on its front page. But pro-European The Guardian opted for the headline “small island”, calling Brexit “the biggest gamble in a generation”.

On Friday, Johnson emphasised unity and is avoiding any major celebrations that might exacerbate divisions. He was seen hosting a special cabinet meeting in the northeastern English city of Sunderland, which was the first to declare for Brexit in the 2016 vote.

At 10 pm, he will broadcast an address to the nation, and then host a reception for staff at Downing Street, before a light-show outside No 10. Millions of commemorative 50 pence coins go into circulation.

Ex-MEP Nigel Farage, who has spent decades campaigning to leave the EU, is planning a large rally in nearby Parliament Square — one of several pro-Brexit parties being held around the country. Pro-EU groups have planned candlelit vigils.