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. This is not an actual seating plan of the House, which has only five rows of benches on each side, with the government party to the right of the Speaker of the House of Commons and opposition parties to the left, but with room for only around two-thirds of MPs to sit at any one time. This table shows the number of MPs in each party: ;Notes
Labour, as the largest party not in government, took the role of Official Opposition. The Co-operative Party was represented in the House of Commons by Labour MPs sitting with the Labour and Co-operative designation.
The "voting total" is the effective size of the House excluding vacancies, suspensions, and certain members : the Speaker, two Deputy Speakers who had only a tie-breaking vote constrained by conventions, and seven abstentionist members. This left relevant party voting totals as follows: Con 297, Lab 241, SF 0, Speaker 0.
The "safe majority", "Gov short by", and "Gov + C&S total" are based on the voting totals. The government entered into a confidence and supply agreement to secure a small majority, which shrank due to defections, finally disappearing on 3 September 2019. Hence, the "Gov + C&S majority", calculated as the sum of voting Conservative and Democratic Unionist Party members, less the sum of all other voting members, was negative at dissolution.
The following table is a list of MPs elected, ordered by constituency. Names of incumbents are listed where they stood for re-election; for details of other defeated candidates and the incumbent who stood down in those cases see individual constituency articles. ;Notes
Deputy Speakers
The Speaker nominated Sir David Amess and George Howarth to serve as Temporary Deputy Speakers until the Deputy Speakers had been elected. The election of Deputy Speakers took place on 28 June 2017. Although Deputy Speakers do not resign from their parties, they cease to vote 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. When Sir Lindsay Hoyle was elected Speaker on 4 November 2019 in succession to John Bercow, the post of Chairman of Ways and Means became vacant and remained so when Parliament was dissolved on 6 November.
By-elections
By-elections are held for seats that become vacant. John Mann vacated the seat for Bassetlaw on 28 October 2019, and the Speaker John Bercow vacated his Buckingham seat on 4 November 2019. The seats remained vacant until dissolution and the election of new MPs in the general election on 12 December 2019.
Defections and suspensions
The label under which MPs sit in the House of Commons can change if they leave or are suspended from or expelled by their party. When suspended, they effectively become independents. This Parliament has had an unusually large number of these changes, resulting in the number of MPs sitting as independents rising to its highest level since the Ballot Act 1872. The Conservative and Labour parties lost numerous MPs through suspensions and defections to other parties. In February 2019, 8 Labour and 3 Conservative MPs formed a new grouping, Change UK. That grouping experienced a split in June, with some of its members resigning to form The Independents. 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. Later the same day, the Conservatives expelled 21 of their MPs for voting against the government, 10 of whom were later readmitted to the party on 29 October.
Progression of government majority and party totals
