Party politics has always been about factions – gangs of like-minded individuals getting together to promote a particular cause or point of view.
But Brexit has taken the natural tendency of MPs to plot and conspire with each other to a whole new level.
Like the rest of the country, the 2016 EU referendum divided MPs into two tribes – Leave and Remain.
For some MPs, these opposing visions of Britain’s future place in the world exert a far more powerful pull than party loyalty.
They sometimes find they have more in common with MPs in other parties who share their view on Brexit than those on their own side.
They rebel against their party leadership to vote for what they see as a bigger cause, even if the term “rebel” has ceased to have much meaning in the current chaotic climate.
MPs are described as rebels one day, for voting against their party leadership, only to become loyalists the next day and vice versa.
It will only get more intense when MPs return from their summer break and gear up for the “meaningful vote” they have been promised on any deal Theresa May strikes with the EU.
Some hope, or fear, that it could lead to a permanent reshaping of the political landscape as the big parties break apart and reform into new ones.
But for now, here is a guide to the main factions in the Commons:
Theresa May loyalists
Government ministers, basically – there are just over 100 them out of a total of 316 Tory MPs – and those backbenchers who support Theresa May’s Brexit policies, or at least are not willing to vote against them and threaten her leadership.
Most Tory MPs fall into this category but it is not enough for Mrs May to be sure of winning key Commons votes, even with the support of the DUP’s MPs, who unlike Mrs May backed Leave in the EU referendum.
Ten members of Mrs May’s government have quit in recent months – most of them because they are against her Chequers plan for post-Brexit trade, although Defence Minister Guto Bebb quit because he is in favour of it. Mr Bebb thought she had caved in to the hard Brexiteers (see below) over customs legislation.
Tory hard Brexiteers
Sixty Conservative MPs, headed by Jacob Rees-Mogg, are members of the European Research Group – a pro-Brexit lobby, who are against Theresa May’s plans for trading arrangements with the EU.
They are well-organised and highly motivated and the PM’s continued survival in Number 10 is, largely, in their hands.
The rebel ranks have been swollen by ex-Foreign Secretary Boris Johnson, former Brexit Secretary David Davis and his deputy Steve Baker.