The House of Commons continues to struggle to break the Brexit deadlock.
MPs have rejected the UK’s withdrawal agreement with the EU three times and have twice voted down all the alternative options put forward.
An explanation for this stalemate can be found not only in MPs’ deeply-held and divergent views on Europe but also in the fluid political make-up of the House of Commons.
What was the situation in 2017?
Image copyright PA Image caption The DUP have supported the Conservatives since 2017 but will their agreement survive Brexit?
No political party won a majority at the 2017 election, which resulted in a Hung Parliament.
After the poll, the Conservatives agreed a parliamentary pact – officially known as a confidence and supply agreement – with the Democratic Unionists.
This arrangement gave Theresa May’s government an overall majority of six – in other words, the Tories and DUP had six more MPs elected than all the other parties combined.
But in reality it had what is called a working majority of 13. That’s because Sinn Fein – which currently has seven MPs – historically does not take up its seats.
Excluding Commons Speaker John Bercow and his non-voting deputies, Tory Eleanor Laing and Labour’s Lindsay Hoyle and Dame Rosie Winterton, Theresa May has typically needed to get the backing of 320 MPs to get a majority in Commons votes.
For the first year or so, the government got its legislation through Parliament quite comfortably but as Mrs May has found to her cost, things have become much more problematic in recent months.
Image copyright AFP Image caption Anna Soubry (centre) and Sarah Wollaston (right) are among those to have left the Conservatives
The government’s already slim working majority – the smallest of any new government since the 1970s – has been further whittled down this year.
In January, three Conservative members of Parliament – Sarah Wollaston, Heidi Allen and Anna Soubry – quit the party to join the Independent Group of MPs.
Then on Monday, former minister Nick Boles resigned the Conservative whip over Brexit and said he would be sitting as an Independent Progressive Conservative.
What’s the current state of play?
Image copyright AFP Image caption Labour has suffered its own casualties – losing more than a dozen MPs
As it stands, Theresa May currently has a working majority of six. This will fall to five if Labour wins the Newport West by-election on Thursday.
The seat has been vacant since the death of Paul Flynn in February. Labour has held the seat since 1987 and Mr Flynn re-gained it with a majority of 5,658 two years ago.