The Parliament was marked by extraordinary political turmoil as Governments led by Theresa May and Boris Johnson were unable to win a series of important votes on the issue of Brexit.

Below are graphical representations of the House of Commons showing party strengths directly after the 2017 general election, at important intermediate points, and immediately prior to dissolution.

Although Deputy Speakers do not resign from their parties, they cease to vote (except to break ties) and they do not participate in party-political activity until the next election.

As the only contesting member from the government side, Eleanor Laing's name did not appear on the ballot paper, and she was duly declared First Deputy Chairman of Ways and Means.

The Liberal Democrats have made a gain of 8 seats since the opening of Parliament, including some former Change UK members.

The government lost its majority on 3 September 2019, when the Conservative MP Phillip Lee defected to the Liberal Democrats.

Whip restored 29 October alongside after meeting with the Prime Minister; standing down at the next election or agreed to support his Withdrawal Agreement if re-elected.