Speculation swirled this morning that a Conservative MP was set to quit over the Government’s approach to Brexit. Eventually, a name emerged – Stephen Phillips, MP for Sleaford and North Hykeham, was going. But would it be a Soft Stexit, merely not standing again at the next election, or a Hard Stexit, triggering an instant by-election?

It turns out to be the latter: Phillips has resigned with immediate effect. So immediate in fact that he apparently couldn’t find time to inform the Prime Minister before announcing the news. There will therefore be a by-election in his Lincolnshire constituency.

What are his reasons?

The top line is dissatisfaction with the way Brexit is being handled – Phillips went on the record to express his unhappiness a few weeks ago. But it isn’t quite clear why he feels he must now resign. After all, things have broadly moved in his direction in recent months. He supported Leave in the referendum. Leave won, and the Government is implementing it. He demanded a bigger role for Parliament in the process. Yesterday’s High Court judgment goes some way to providing that.

It seems natural to look to his resignation statement for further explanation:

“…it has become clear to me over the last few months that my growing and very significant policy differences with the current Government mean that I am unable properly to represent the people who elected me.”

There are two parts to that sentence. The first is the “growing and very significant policy differences” between Phillips and Downing Street. Perhaps he simply means the Government’s declared aims in May’s conference speech about leaving the EU, and its continued insistence on retaining the prerogative right to trigger Article 50. Or perhaps there are other policies in addition to that on the EU with which Phillips disagrees. Either way, it’s unusual for an MP to feel they must resign because the Government is making them into a rebel – most MPs in that situation simply stick to their guns and start rebelling.

A better insight into his motivations might lie in the second half of the sentence: “I am unable properly to represent the people who elected me.” That implies that Phillips believes his electors support the Government over the policies that he disagrees with, making his position untenable as he would like to oppose things that his constituents want him to support. That sounds like a more understandable source of discomfort in his daily life, finding himself conscience-bound to be routinely at odds with his electors on issues which are both important and constantly in the headlines.

There might also be unspoken aspects to consider. Phillips is an accomplished lawyer who enthusiastically backed May for the leadership – he might reasonably have hoped to become one of the Government’s law officers when she took power, and therefore could reasonably be disappointed that that did not happen.

Some have interpreted the coming by-election as “a Brexit by-election”, even going so far as to suggest Phillips is seeking a ballot in order to challenge the Government’s agenda. That doesn’t sound plausible.

For a start, he isn’t standing; this isn’t David Davis putting himself forward as a champion of ancient liberties, or Zac Goldsmith standing as an anti-airport independent. If Phillips was seeking a new mandate to oppose what he sees as excessively Hard Brexit, that could be a different matter. But in reality he’s simply vacating the seat.

It’s inconceivable that the new Conservative candidate wouldn’t support the official position of leaving the EU, and the numbers suggest they’d have a good chance of victory even if the Lib Dems or someone else tried to make it into a “Brexit by-election”. The 2015 General Election result went like this:

Conservative 34,805
Labour 10,690
UKIP 9,716
Liberal Democrat 3,500
Lincolnshire Independents 3,233

In short, this is not Richmond Park – the electorate supported Leave, and there can be no fantasy of a ‘progressive alliance’ of Lib Dem and Labour voters teaming up to win the day. Together, UKIP and the Conservatives got almost 72 per cent of the vote in 2015 while Labour plus the Lib Dems secured just 23 per cent. According to psephologist Chris Hanretty’s model, Sleaford and North Hykeham voted 61.5 per cent Leave in June. Phillips’ comment that he is “unable properly to represent the people who elected me” further suggests that if anything the voters here are more keen on a full-fat Brexit than he is.

So what will happen next? Rather than the snub to the Government that some Continuity Remainers seem to be vainly hoping for, the constituency will elect someone else who supports leaving the EU. In all likelihood, given the size of the majority and the political context, that person will be a Conservative.

If there’s a story at all, it seems most likely to be the question of whether UKIP can get their act together and overtake the Labour Party for second place, or whether May’s commitment to Brexit combined with the People’s Army’s ongoing troubles will see their vote share decline. UKIP have a long tradition of seriously messing things up only to suddenly be granted an opportunity to regain momentum by chance political circumstance – they’ll be hoping it might happen again.