What the Commons could look like after the July vote

Four scenarios: from a hung parliament to a Labour majority

- IAN JONES

Here are four possible outcomes for the general election, from the Conservatives losing seats but remaining the largest party, to Labour making enough gains to form its first government in 14 years.

Each scenario includes examples of the size of the swing and the turnover of seats that could take place.

Conservatives lose majority but remain largest party

The general election is being held using new constituency boundaries, which means it will not be possible to compare the results directly with what happened at the last general election in 2019. In order to judge how well the parties do at the election, and to work out which seats they need to win to form a government, a set of notional results for the 2019 election has been calculated to show what would have happened if that contest had taken place using the new boundaries.

These notional results have been compiled by professors Colin Rallings and Michael Thrasher of the University of Plymouth, on behalf of BBC News, ITV News, Sky News and the PA news agency, and will be used as the basis for reporting the gains and losses at the general election. Under these notional results, the Conservatives won 372 seats in the 2019 election.

A total of 326 seats are needed for a majority in the House of Commons, therefore the Tories can afford to lose up to 46 seats before dropping below this threshold. A uniform nationwide swing in the share of the vote at the election from Conservative to Labour of 4.2 percentage points would likely be enough to wipe out the Tory majority, as it would involve 47 Conservatives losses – 40 to Labour, five to the Liberal Democrats and two to the SNP – and reduce them to 325 seats.