Chris Heaton-Harris is MP for Daventy.

As the European Referendum Bill makes its way to the House of Lords, most eyes in Westminster focus on the fine detail of the Bill. However, for the country as a whole, one important question remains: when will the referendum take place?

Bearing in mind it can be expected that the referendum will fall on a Thursday, there are very few appropriate dates on which it can now be held.

Back at the Summer European Council, a working group was set up to examine what a renegotiated settlement could look like, based on the four themes that the Prime Minister outlined: competitiveness, accountability, the relationship between those countries that use the Euro and those that don’t, and immigration/freedom of movement.

It is expected that this working group will report back at the December Council meeting (17th-18th December of this year), and it is highly unlikely it would be able to examine any proposals concerning the fourth theme until after the Polish parliamentary elections on the 25th October. In fact, following the Polish elections, we can expect to see a massive diplomatic push from the Prime Minister, Chancellor of the Exchequer and Foreign Secretary, involving visits to every European capital and pushing for more concrete proposals.

There will then be discussions, probably heated, at the December European Council, perhaps ending in a decent bun fight. This will be followed by a yet more concerted diplomatic effort by the Prime Minister and others to try and get a deal as quickly as possible in 2016.

There are two alternative date ranges that then open up for the referendum. If things go unbelievably well in negotiations then, instead of just a reporting-back process at the Spring European Council meeting, there could be an agreement – and then a referendum date could be set for one of the first three Thursdays in July.

My hunch, though, is that the referendum will fall later in the year.

I think we can probably expect to see that reporting back of progress at the Spring European Council meeting – but not much more, since the government will doubtlessly not want to distract from the important polls that are already scheduled to take place on the 5th May of next year, including: elections for the Scottish Parliament; the National Assembly for Wales; the Northern Ireland Assembly; Police and Crime Commissioners in England and Wales; the London Assembly and Mayor of London; and local authorities in many parts of England.

It should be noted that Electoral Commission guidance means that the referendum cannot take place on the same day as these elections, and it is in practice highly unlikely to take place a month either side of the 5th May.

It is thus more than likely that the diplomatic work started after the December European Council will continue, with the aim of getting to the position in which the Prime Minister can detail the outcome of the renegotiation at the end of June during the Summer European Council meeting.

Obviously, the outcome of these discussions will determine the date of the European Referendum, but there are a number of other factors that come into play:

Law : The European Referendum Bill (when it becomes law) states that any referendum has to happen before the end of 2017.

Administration : The UK actually takes over the European Council Presidency for six months between July and December 2017. It would be highly unlikely that the Prime Minister would want a referendum on the membership of the European Union whilst the UK holds the Presidency of the Council.

Nature : It is unlikely that we will have our European Referendum in the depths of a British winter.

Elections : The French elect their next President in April/May 2017 and the Germans have parliamentary (federal) elections on the 22nd October 2017. Whilst it is a commonly held belief that the French are not keen to help David Cameron in his renegotiation push, it really shouldn’t be underestimated how unpalatable and potentially destabilising a UK referendum on EU membership would be in these elections. These immovable dates both give David Cameron some extra political negotiating power and almost certainly mean the referendum date will not be in 2017.

So I think we will arrive at a deal by the Summer European Council meeting, allowing the Prime Minister to return home from Brussels with his renegotiated settlement and set the date for the referendum for either the end of September or early October 2016.

From here, the various provisions of the EU Referendum Bill (by then the EU Referendum Act) and practical government management come into play.

There has been some speculation as to whether the Prime Minister would want to allow some of his Ministers to campaign actively on the “leave” side of the referendum campaign. I think there is an opportunity in this timescale that would allow the Prime Minister to let his Ministers campaign as they wish – without actually disturbing the practical day to day business of running the Government.

Let’s say that he returns from the Summer Council meeting with the conclusions of his negotiations. Parliament heads into recess a couple of weeks afterwards and it would be completely legitimate for the Prime Minister to say that parliament will not reconvene in September and therefore only return after the referendum. This gives the Government a short period of time up to the start of the Summer Recess to deal with any urgent business and, following this, Ministers could be given free reign to campaign as they wish.

August is normally a quiet political month domestically, and the 28 day purdah provision currently contained within the EU Referendum Bill could come in peacefully during August and last into September, without the concern of Ministers using the Dispatch Box to further the case of one side of the argument over the other.

So I’d expect the date to be between the middle of September and the beginning of October, 2016. In fact, if I was a betting man, I’d stick a fiver on Thursday 15th September 2016.