With 650 days (and 10 hours, according to our handy clock) from today left before the official leaving date, the government’s top people are set for two years of intense and almost certainly fractious bartering.
*Read more*: Meet the four men in charge of the EU’s Brexit negotiations
With no real precedent for the Brexit process (barring Greenland’s decision centred on fishing rights), the personalities involved will be vital to setting a good starting tone to the long diplomatic slog.
While the Conservative government is currently running a minority government, with no deal yet signed for the support of the Democratic Unionist Party (DUP), we still have some idea of the probable shape of negotiations and who will carry them out.
Here are the four key figures in the first few days of negotiation.
The secretary of state for exiting the European Union has one of the least catchy titles in government, but he has emerged as the lynchpin in the negotiations. International trade secretary Liam Fox has faded into the background and foreign secretary Boris Johnson has mainly been diverted elsewhere, leaving Davis in charge.
His portfolio is one of the most challenging in British political history: agreeing the divorce bill (estimated at €60bn by the Centre for European Reform), securing a transitional deal and trying to keep as much access as possible for British businesses to the EU’s Single Market in the long term.
He previously had negotiating experience, including on Europe, as foreign office minister from 1994 to 1997 under John Major.
A leading figure in the Brexit campaign, Davis lost the Conservative party leadership to David Cameron in 2005. After that victory, the former Prime Minister said Davis would be “"a vital part of the team in the future", words which seem almost prophetic now.
*Read more*: Davis blasts EU's "illogical" stance on Brexit negotiations
The European Commission’s chief negotiator, who will spend the day (and many more after) with Davis on Monday, is steeped in the European Union. A former member of the European Parliament, EU commissioner and then vice-President for the internal market, Barnier has emerged as Brussels’ main man.
The Frenchman has more than 20 years of experience of diplomacy, including as a minister in the French government in charge of European and foreign affairs, amongst other things.
He also brings strong connections to other European leaders, having spent nine years as the vice-president of the European People’s Party, a group of centre-right leaders including Angela Merkel (which David Cameron’s Conservatives left in 2009).
*Read more*: Michel Barnier: "No deal or bad deal" not our aim in Brexit talks
*Oliver Robbins, permanent secretary, UK department for exiting the EU*
Olly Robbins is the man charged with directing the civil service’s efforts to negotiate Brexit – although in reality every department in Whitehall will face an enormous task.
Robbins is a civil service lifer. He joined after graduating in philosophy, politics and economics (PPE) from Oxford, rising quickly through the ranks via the Treasury, Downing Street and the National Security Council where he served as David Cameron’s national security adviser.
Before being appointed to head an emergency Brexit unit last July Robbins was responsible for immigration and borders at the Home Office. That experience might come in handy with freedom of movement – one of the four pillars of the Single Market – set to be a central part of the debate.
*Read more*: David Cameron sets up civil service "Brexit unit"
*Sabine Weyand, European Commission's deputy chief negotiator*
Robbins’ counterpart on the European side will be Sabine Weyand. The German national will bring a detailed knowledge of British politics as well as a command of the often confusing mass of EU bureaucracy.
Weyand spent part of her first degree studying politics at the University of Cambridge and then progressed to a surely fascinating doctorate: “EC Common Transport Policy – a Study in EU policy-making.”
Her long career in the European Union’s equivalent of the civil service has spanned aid, trade, and external relations, including OECD nations and China, before becoming a director in the secretariat-general of the European Commission.
She was appointed as deputy chief negotiator in October, moving from a trade role.
*Read more*: May accuses Europe of aggressive first shot in Brexit negotiations
Brexit negotiations have finally begun in Brussels, almost a year to the day after Britain voted to leave the European Union. David Davis, the UK Secretary of State for Leaving the EU, and the bloc’s Chief Negotiator for Brexit Michel Barnier met in Brussels for the first day of talks on Monday...