• David Cameron likely to announce his resignation as Prime Minister today • He'll have to outline Government's battle plan for untangling itself from EU • Triggering Article 50 of the Lisbon Treaty is the only formal way out • That will set two-year period for negotiating new trade arrangements • Some Leave supporters say we could try other routes to a deal • Cameron unlikely to stay as PM for more than a few months after losing • Pro-EU MPs could try to block us leaving single market despite Brexit vote • Boris Johnson could be installed as Prime Minister in coming weeks Britain has voted clearly in favour of leaving the EU, but that is just the start of a very long process before they officially untangle themselves from the network of institutions in Brussels. The historic result could see us embarking on a path to an enlightened era of prosperous global trade, freed from the shackles of unelected Brussels bureaucracy. Or if you listen to the Remain camp, it could be the end of Western civilisation, with the continent descending into war and pensioners going hungry. Whichever side of the European argument you fall, the only certainty seems to be that things from now on will be pretty lively. So what will the next 100 days of Brexit Britain look like?
A shattered David Cameron will shortly appear outside 10 Downing Street to concede defeat. The Prime Minister will promise to implement the wishes of the British people, but his speech will be necessarily short on detail. His main focus in his speech outside Number 10 - expected around 7am - will be to appeal for stability and unity to avoid financial and political chaos. Only semi-independent Greenland has quit the EU before, and that was 30 years ago when the island had a population of just 56,000. Mr Cameron is likely to announce his resignation as Prime Minister but will probably hold off on a dramatic announcement about his own future in the immediate aftermath of a Brexit vote in order to ensure some kind of stability in government. It is almost impossible that his premiership will be able to survive the defeat for long. He could fire the starting gun on a Tory leadership contest, which Brexit champion Boris Johnson would almost certainly win. On the financial and economic front, the Treasury, Bank of England and European Central Bank will activate contingency plans to shore up the currency and inject liquidity to banks to ensure the system keeps working.
EU leaders are due to gather for a summit in Brussels, at which there will be only one topic - the Brexit vote. They could even bring the meeting forward by a few days if their anxiety is great enough. Mr Cameron is expected to formally notify them of our intention to leave, trigger Article 50 of the Lisbon Treaty - the legal process for quitting the 28 nation bloc. That starts the clock on a two-year period during which we negotiate a new set of arrangements in areas such as trade, justice and reciprocal visas. However, the PM may hold off as some Leave campaigners do not want to invoke Article 50 at all, believing it puts our negotiators at a disadvantage. Instead we could try to force the EU to strike a deal without imposing a time limit - but that may depend on whether other states are willing to play ball. European commission president Jean-Claude Juncker has already warned that 'deserters' will not be treated kindly.
As the immediate shock of the Brexit vote eases, the government machine gears up to the task of negotiating a new deal with the EU and replacing other bilateral trade agreements. Despite volatility on the markets, the public will almost certainly be surprised to find that little changes in their everyday lives. Importantly, there is virtually no chance that George Osborne's threat of a post-Brexit "punishment" Budget will happen. That is partly because victorious Conservative Eurosceptics will have demanded Mr Osborne is moved from No11, but also because the hit to the real economy will not have been as immediate as some made out. On July 6, Mr Cameron will be able to lead the government response to the publication of the long-awaited Iraq Inquiry report. Shortly afterwards he is due to attend a Nato summit.
Parliament is due to rise for its summer break, but there will be little rest for ministers as they are consumed by the negotiations. The civil service has been quietly contingency planning for the possibility of our departure, with every department set to be affected by the seismic changes. But Mr Cameron, if he is still in place, will be largely peripheral to the process. Having been so closely associated with the Remain campaign, it is almost inconceivable that Mr Cameron would be regarded as a credible head negotiator. It is possible that another, Brexit-supporting minister such as Michael Gove could be appointed to oversee the work. Vote Leave said the government should invite figures from other parties, business, the law and civil society to join the negotiating team to 'get a good deal in the national interest'. By now the Tory leadership contest is likely to be in full swing. The party's rules mean MPs nominate two candidates, who are then put forward for an election by the wider membership.
If the Conservative leadership takes a similar length of time as in 2005, this is around when the successor to Mr Cameron could be announced. Given the need for someone to take charge of the talks, it is likely there would be a strong desire to move as fast as possible. Mr Johnson would be in a position to win a very strong mandate, as the politician who did the most to deliver the Brexit vote.
Parliament is due back, and while the early autumn sitting it usually viewed as a sop to those who complain MPs do not work hard enough, this year it could be extremely busy. Vote Leave has called for legislation in the current session of Parliament to 'end the European Court of Justice's control over national security and allow the government to deport criminals from the EU'. The Brexiteers have also pledged abolish the 5 per cent rate of VAT on household energy bills by amending the Value Added Tax Act 1994. Other parliamentary actions promised by the Leave campaign include ending the automatic right of all EU citizens to enter the UK, and - finally - repealing the European Communities Act 1972 (Repeal) Bill. That is the legislation that guarantees the supremacy of EU law to domestic rules. However, it is not clear how fast the Brexiteers will be able to cut the ties to Brussels. Around three quarters of MPs support EU membership, and some are already considering how that weight of numbers can be used to limit the impact of a Leave vote. There could be efforts to defy the public will altogether, or keep us in the single market rather than quitting the bloc altogether. Iain Duncan Smith has said that MPs who ignore the outcome of the referendum it would trigger a 'constitutional crisis' and potentially a snap general election.
The political party conference season is always frantic, but this year it will have an even greater significance. The realignment of politics set in train by the referendum would have been huge for Britain and for Europe. Just after the first hundred days draws to a close, the new Tory Prime Minister could take to the stage in Birmingham to address activists. Mr Johnson - if he has emerged victorious - would be able to argue that the UK has made a start in its new life independent from Brussels.