There is the question of who will do the negotiating for Britain.
The most senior members of the government, David Cameron, Chancellor George Osborne, Foreign Secretary Philip Hammond and Home Secretary Theresa May – are all Remain supporters and some of them may choose to depart when the PM stands down.
During the campaign, the Leave side said that it would be happy for existing ministers and senior civil servants – including cabinet secretary Sir Jeremy Heywood to lead the negotiations although they would expect senior Leave figures to play a very prominent role, as well as figures from other parties, business, law and civil society.
Now, however, it seems certain the next prime minister, whoever they may be will take charge of the process.
Could this be Boris Johnson or Michael Gove – both of whom were tipped for major promotions whatever the outcome of the vote.