Brexit: 'We're out!' after 47 years, but what's next?

But the joy was real among the thousands of Brexiteers rallying in London's Parliament Square as the UK left the European Union legally on Friday (31 January).

The day marked a milestone in European history as the EU went from 28 member states to 27 and lost 66 million citizens.

"To mark this milestone in the United Kingdom's history", a new 50p coin would be circulated on the day, the Royal Mint announced in advance. The new coin features the inscription "peace, prosperity and friendship with all nations".

In Brussels the divorce was marked with a red-blue-white light show at the Grand Place while the UK flag was lowered outside and inside EU institutions. MEPs sang "Auld Lang Syne" in the last plenary with UK MEPs in their seats, a song that is based on a Scots-language poem.

Scotland left the European Union on Friday as part of the UK, but a majority of the Scots would like to return, according to opinion polls.

A majority in the Scottish parliament voted last week in favour of holding a second referendum on independence while first minister, Nicola Sturgeon, keeps all routes open for her country to return to the EU club as soon as possible.

At Parliament Square in London thousands of predominantly-white male Brexit fans celebrated the end of the UK's EU membership by singing "Rule Britannia" and other national songs while waving the Union Jack. Alcohol was banned from the square.

The lyrics were displayed on a big screen but with a bit of a delay, however most of the fans in the muddy square knew their national classics by heart and managed to keep in sync.

They watched highlights from the 47 year-long EU membership on a big screen, including recordings of former prime minister Margaret Thatcher, who famously demanded "we want our money back" from Brussels.

Apart from a short TV speech, current prime minister, Boris Johnson kept away from any public appearance on the Brexit evening - most likely in order to not split his already highly-divided people further.

It was instead former Ukip leader, Nigel Farage, and his speech to the crowds together with the count down that formed the culmination of the celebrations.

"The single most important moment in the modern history of our great nation", Farage called the moment, that saw grown men shed a tear and a lot of kissing and hugging.

Now, it is over to "Boris", Farage told them, while promising to keep a good eye on him.

Meanwhile, inside 10 Downing, Johnson celebrated the Brexit hour with his closest allies and ministers.

As the TV broadcast feed failed in the most important minutes, the prime minister turned to a manual countdown, using a real gong to mark the Brexit moment.

What's next?

The coming eleven months are planned to be a standstill transition period where the EU and the UK will discuss their future relations.

Johnson is expected to deliver a key speech on Monday (3 February) about the UK's negotiation position, while the European Commission's lead negotiator, Michel Barnier, is set to respond by revealing also on Monday what the EU mandate for the talks will be like.

Johnson is said to prefer a deal like the one the EU has with Canada - but it could also end up with a no deal and future trading based only on World Trade Organisation terms.

Signs of Johnson wanting to play it hard have emerged.

His foreign minister, Dominic Raab, sent a telegram last week to all overseas missions telling UK diplomats to distance themselves from EU diplomats and sit separately from them in international organisations.

From the EU's side Barnier has demanded a "level playing field", meaning trading between the EU and the UK must be based on EU rules in order to not undercut standards.

Johnson is expected to stick to the EU rules on food, workers rights and environment but the question is if the UK would accept a judgement from the European Court of Justice if not keeping in line with EU rules.

Meanwhile the EU is going to be busy with its own internal affairs, such as migration policy, the green deal or its new seven-year budget.

EU budget discussions were always difficult, but this time round it will be more complicated without the UK contribution.

The UK has been the third- or fourth-largest contributing country to the EU budget in recent years, paying around 13 percent of the total budget.

The talks on the UK's future relationship with the EU could turn "nasty", creating anger towards the EU, Lord Kerr of Kinlochard warned in an interview with the Sunday Times.

Lord Kerr drafted the famous Article 50 in the EU treaty, which allows for a country to leave the Union.

"As it becomes clear that the negotiations will not end happily, people will tend to blame the foreigners", he predicted, adding that without the UK, the rest of the EU itself will also change.

"We were, with the Dutch and the Danes and then the other Scandinavians when they arrived, the keenest on free trade with the outside world", he said. The Baltic countries would also be more worried after losing the British, who were traditionally strong in standing up to the Kremlin.

But history's judgement of Brexit will above all hang on how well the UK and the European Union are doing economically after Brexit, which in turn might depend on a well-cut trade deal that serves the long-term interest of both parties.