Political preview 2016: What to look out for in the year ahead from the EU referendum to the US elections

The year will also see crucial votes on Trident and Britain's EU membership, while Jeremy Corbyn turns 67

The vote on Trident’s successor in April will expose Labour divisions (Getty)

Early January: Shadow Cabinet reshuffle

Jeremy Corbyn could sack critics and promote supporters as early as the first week of January. A well executed mini reshuffle could strengthen his hand.

18-19 February: EU summit in Brussels

David Cameron hopes to seal his renegotiation deal. If he fails, he will have to wait for the March or June summits and postpone his plan for a summer referendum.

16 March: Budget

George Osborne got lucky with the Office for Budget Responsibility’s independent forecast in November, which allowed him to pay for a U-turn on tax credits cuts, but the forecast may not be so kind next time. He may also have to legislate to deny in-work benefits for three or four years, depending on what is agreed in Brussels.

Mr Corbyn replies to the Budget, which will be one of his biggest tests.

April: Trident vote

Mr Cameron has promised a vote in Parliament “on the principle of continuous at-sea deterrence and our plans for Successor [the replacement system for submarine-based Trident nuclear missiles]”, but he hasn’t decided when to hold it. More divisive for Labour than Syria, because party policy is clear (in favour, for now), while Corbyn is equally clear (against). Even if Maria Eagle, shadow Defence Secretary, and Hilary Benn, shadow Foreign Secretary, have been moved, Tom Watson, the unsackable deputy leader with his own mandate from party members, is in favour of Trident’s replacement. Another free vote for Labour MPs is likely.

5 May: elections

Scottish Parliament, Welsh Assembly, Northern Ireland Assembly, London Assembly and Mayor, local government in England, Police and Crime Commissioners in England and Wales. Labour MPs have long pencilled in this date as the moment they make their move, but Mr Corbyn played down expectations successfully in the Oldham by-election. Can he do it again?

26 May: Jeremy Corbyn’s birthday

He will be 67.

June/July: early EU referendum

If Mr Cameron gets a deal in February, there will be a dash for a summer vote, to give anti-EU Cabinet ministers least time to mobilise. Will Theresa May or Iain Duncan Smith lead the “Leave” campaign? Alan Johnson, the Labour former Cabinet minister, will lead the Remain campaign, with Cameron presenting himself as both above the fray but also recommending that we stay in. Mr Corbyn, historically opposed to the EU, will probably take a low profile.

September/October: Late EU referendum

If the Prime Minister cannot get a deal in February, the timetable for the referendum will slip to the autumn.

25-28 September: Labour conference, Liverpool

Mr Corbyn may “clarify” the rules to make it harder to oust him: he would ensure that the incumbent leader is automatically on the ballot paper if there is a challenge. He may also change the rules to strengthen his control of the National Executive; give more power to £3 registered supporters; and transfer policy-making from the National Policy Forum back to annual conference. He will probably try to change party policy on Trident, which since 1989 has been to support the UK’s nuclear weapons programme.

2-5 October: Conservative conference, Birmingham

Another beauty parade for the candidates to succeed David Cameron as leader.

8 November: US elections

President Donald Trump? Or President Hillary Clinton, a Democratic president in many ways to the right of Mr Cameron?