The UK has voted to leave the EU. Here is what is likely to happen next.
Prime Minister David Cameron will make a statement.
He want to reassure the country and the financial markets about the prospects of a smooth transition. He may also address the implications for his own position of having failed to take the country with him. Boris Johnson, Michael Gove and other pro-Brexit Tories have publicly backed him staying in Number 10 to oversee negotiations but many Westminster observers believe his position will be untenable.
Trading on the London Stock Exchange could be suspended.
Chancellor George Osborne has discussed the radical step with Bank of England Governor Mark Carney in the event that Brexit triggers a "Black Friday" crash. The pound overnight dropped to its lowest level in more than 30 years at the prospect of the UK quitting the bloc. Shadow chancellor John McDonnell has said he expects the Bank of England to intervene given the scale of the turbulence.
An emergency EU summit?
Leaders are scheduled to gather on Tuesday but the meeting could be brought forward to deal with the fallout of the dramatic change, which could have huge ramifications for the future of the entire project. A press conference is due to take place later this morning with the heads of the European Commission, Council and Parliament - and Mark Rutte, prime minister of the Netherlands which holds the rotating presidency.
Negotiations over the terms of the UK's exit.
Article 50 of the 2007 Lisbon Treaty envisages a two-year negotiation to draw up a withdrawal agreement. If no deal is reached - and any of the other 27 states block an extension of talks - the EU treaties simply cease to apply to the state in question at the end of the period, leaving it to operate under international rules set by bodies such as the World Trade Organisation (WTO). Mr Cameron has previously said that he would kick off the withdrawal process immediately but Brexiteers say the process does not have to begin straight away - or indeed at all. Tory minister and leading Leave campaigner Andrea Leadsom said Britain could negotiate a bilateral agreement with a "presumption of continuity" of free trade.
A Government reshuffle?
Assuming he stays on as Prime Minister, Mr Cameron will be under enormous pressure to promote senior Leave figureheads such as Boris Johnson to key positions in a new-look ministerial team. Chancellor George Osborne is seen as particularly vulnerable to the axe after angering Conservatives with stark warnings about the impact of leaving on the economy which they condemned as "scaremongering".
Another independence referendum in Scotland?
Every area north of the border voted in favour of remaining in the EU, prompting former SNP leader Alex Salmond to state it was "almost certain" that the country would be asked to reconsider its place in the United Kingdom. Voters rejected a breakaway in 2014 but in the manifesto on which it won a fresh term in power at Holyrood last month, the party left open the option of reopening the question in the event of a "significant and material" change in circumstances such as being forced out of the EU against the will of a majority of its people.