Nearly exactly a year after Britain's seismic referendum to leave the bloc, the EU's chief negotiator, Michel Barnier of France, welcomed his counterpart David Davis with a cheery handshake at the European Commission in Brussels. "That will be in our mutual interest, but we 27 will formulate our interests very clearly and hopefully together".
In particular, some agreement must be reached on issues including how much money Britain owes to Brussels on departure, and on the rights of European Union citizens living in Britain after Brexit, before talks on a future trading and political relationship can begin.
Barnier said: "Today, we are launching the negotiations and orderly withdrawal of the United Kingdom from the EU".
Earlier, Boris Johnson said the talks would lead to a "happy resolution" for both sides.
A week after the negotiations began, the EU Commission will report back to the 27 members of the European Union, excluding the UK.
Au contraire, said Michel Barnier, the EU's chief negotiator, who made clear that Britain first must leave the union, then talk about terms of their future relationship.
Talks are expected to stretch around 16-18 months, with Barnier insisting on sticking to the EU's priorities and negotiating the "divorce bill" before opening up talks on future trading.
David Cameron was the last PM to cancel a Queen's Speech so Parliament could remain in session for two years.
May officially triggered the two-year Brexit process in March when she was riding high in opinion polls, and called for fresh elections shortly afterwards to shore up her mandate for a tough Brexit stance.
European People's Party caucus leader Manfred Weber told German radio station Bayern 2 Monday: "Our big problem is that we have no picture, no idea at all what the British want".
Davis said he hopes to agree "a deal like no other in history".
Britain will be the first country to ever depart the EU.
Despite pressure from the Labor opposition that May should unilaterally recognize the rights of the community, the head of government conditioned that measure to a reciprocal gesture for the British living in the EU. They should finally tell us what the aim is.
This includes preparations for new bills on customs and immigration.
Mrs May's election debacle has revived feuding over Europe among Conservatives that her predecessor David Cameron hoped to end by calling the referendum and leaves European Union leaders unclear on her plan for a "global Britain" which a lot of them regard as pure folly. "In a second step, we will scope our future partnership".
The most important ask from business - nearly more important than what the end result looks like - is that we have a smooth path to get there.
While Britain's economy has shown unexpected resilience since the Brexit vote, there are signs of weakness.
There will be haggling over the terms, over money, but "the most important thing is to raise our eyes to the future. and think about the deep and special partnership that we want to build with our friends", he said.
Ms Davidson called for an "open Brexit" that put the needs of the economy before cutting immigration, although a Scottish Conservative spokesman later denied suggestions that she was seeking continued membership of the single market, which requires the free movement of European Union nationals.
SOME politicians don't realise when they have it so good and often find it hard to resist the urge to go after even more power - quite often just for the sake of it.