It is probably the biggest split in the country since the English Civil War. Mothers no longer speak to daughters, lifelong friends hesitate before bringing it up, and now it seems Brexit has divided Watford's MP from his Conservative Association.

If political blogger Guido Fawkes is correct, the three permanent employees of the association have resigned to take up roles with a professional group set up to campaign for Watford MP Richard Harrington.

One reason? "Brexit-obsessed" activists, the MP says. But why would the MP take this step?

Read more: Richard Harrington denies rift with Watford Conservative Association

There are two things to be aware of: the MP next door, South West Herts' David Gauke, last week survived a no-confidence vote from his own Conservative Association, and Labour were breathing down the Conservatives' neck in Watford at the last general election.

Mr Gauke felt the no-confidence vote was triggered by Leave.EU supporters angry at his opposition to a no-deal Brexit joining the association to try to force him out. Ever forthright in his refusal to change his position, won by just over two to one.

Mr Harrington appeared on Sky News yesterday (Thursday) to say he would welcome a similar no-confidence vote, as he felt he would win it.

He may be right. Why would members throw out a hard-working and successful MP, who had been trusted with ministerial office, to replace him with an unknown quantity?

Click here to read the Conservative Association's response to Mr Harrington's move

But the unspoken result of Mr Harrington employing the association's three most senior members is that without anyone in those roles it is harder for the association to mobilise against him.

And how certain is Mr Harrington of his association's support come an election? Labour candidate Chris Ostrowski came far closer than anyone predicted in 2017. With a key Labour area of south Oxhey due to be moved into the Watford constituency, and having lost a Tory-supporting area to his Leave-supporting neighbour Anne Main, Mr Harrington has a fight on his hands to keep his seat at any future election.

Perhaps he feels a professionally-run campaign run with his oversight is a safer bet than party members who may not feel he has their interests at heart, and might not turn out to knock on the doors and deliver those leaflets, especially if a Brexit Party candidate arrives in town.

Labour's position on Brexit is hardly clear, but until the European elections this did not seem to harm them. The Liberal Democrats, who do have a clear position, have a firm grip on the council but routinely come a distant third when it comes to Parliament.

As with anything in politics since 2016, any prediction would be foolish.

But Brexit, the great divider, seems to have come between an MP and the people who might help keep him in office.

The Conservatives are supposed to be electoral survivors, but this will be a test of the Watford association's resolution.