With markets jittery and the pound down, time is of the essence when it comes to Britain's formal departure from the European Union. Here are some key potential dates ahead:

SEPTEMBER

British Prime Minister David Cameron says his successor will have to trigger the all-important exit clause that would set the clock ticking on a two-year process for Britain to leave.

The Conservative Party committee has suggested a new leader could be elected in early September — possibly between Sept. 2 and 9 — but it remains unclear if and when that new chief will trigger the exit clause.

EU leaders, meanwhile, meet again in Bratislava on Sept. 16 to discuss the path ahead. Ideally that would fall after the Conservative Party election and before the leaders head to the U.N. General Assembly, which runs Sept. 13-26.

OCTOBER

The new prime minister may choose to call a general election, capitalizing on the confusion in the opposition Labour Party to obtain a new mandate for the moves he or she will have to make. The Conservative Party is also set to hold its annual conference in October.

JANUARY 2017

Several officials have suggested that the exit might be activated on Jan. 1, 2017. The date seems logical, as EU leaders could prepare for it at their end-of-year summit in December.

2019

A Jan. 1 trigger would also provide hope that the two-year process could be wrapped up by Jan 1, 2019, a few months before the next European Parliament elections.

Until Britain leaves, it remains a full member, and while no one wants it to leave, if it has to go everyone is keen to have it gone by the time Europeans choose new legislators in mid-2019.

BEYOND?

The 2019 departure date only works, of course, if the negotiations can be wrapped up in time. If EU partners make it difficult for Britain to leave and the talks bog down, London could ask for an extension. But all 27 remaining EU countries would have to agree, and with the European elections looming, the pressure would be on.