Jeremy Corbyn’s party has a narrow window of opportunity to take control of 34 seats, but Tories are unlikely to call another early poll • General election 2017 - live updates

Labour can win majority if it pushes for new general election within two years

Labour’s hopes of ousting the Tories from power are now within its grasp if a general election is called within the next two years, according to a Guardian analysis of the new electoral landscape.

Analysis of the new marginal seats shows that a swing of just 1.63% to his party would deliver the 34 gains that Jeremy Corbyn needs to make Labour the largest party in the Commons.

Labour’s 2017 result saw its share of the vote rise by 9.6 points to 40% – the largest increase at a single election since 1945 – but gained only 30 seats to bring its total to 262.

The distribution of the new marginals is such that a swing of a further 3.3% to Labour at the next general election would yield almost double the number of seats to 58 and secure a Commons majority of one.

Last Thursday’s general election has left 22 Tory MPs sitting on majorities of less than 1,000 with the home secretary, Amber Rudd, defending a majority of just 346 in Hastings and Rye and the former Northern Ireland secretary, Theresa Villiers, similarly defending a majority of only 353 in Chipping Barnet.

The question of whether Labour could build on its 40% share of the vote depends on whether it can construct further alliances beyond the unique coalition of more affluent voters under 35 and former Ukip supporters it put together last Thursday.

It is possible that the result was “peak Corbyn” but it is certain that Labour will want to win back the skilled, working-class votes and seats they lost to the Tories such as Mansfield and Walsall North, which must be well within their capabilities.



The window of opportunity however, for Corbyn is a narrow one. The much-delayed boundary review of constituencies, which is expected to give a significant boost to Tory chances, does not yet have a firm timetable but is likely to be implemented early in 2019. That could well change the shape of the electoral map once again. Labour needs to push for a general election within the next two years to have a serious hope of being in power.

For the Conservatives the cliff edge has suddenly become much narrower, which may explain why calling an early election to resolve the deadlock may not seem a very attractive proposition for the Tories in the immediate future.

However, it has to be remembered that last Thursday’s general election also delivered a six-point surge in the Conservative vote giving them a 42% share of the vote. They lost 13 seats despite securing the support of 13.6 million voters, just 100,000 short of Margaret Thatcher’s record 13.7 million win in 1987.

The new marginals battleground shows that the Conservatives would gain 19 seats on a swing of only 1% to them. The list of 19, all with a majority of less than 1,000, according to electionpolling.co.uk include previous Labour strongholds such as Bishop Auckland and Penistone and Stocksbridge.

The calculation that a swing of just 1.63% to Labour is needed to secure the gain of the top 34 seats on the Labour target list and deny the Conservatives their title of largest party in the Commons is based on them taking seats from all other other parties. A swing of 1.63% to Labour would see them gaining 24 seats from the Tories, nine from the SNP and one from Plaid Cymru. The winning line, seat number 34, would be Ed Balls’s old constituency of Morley and Outwood.

Labour could also become the largest party if it managed to win 29 seats directly off the Conservatives. This would require a slightly higher swing of 2.01%.

The Guardian analysis assumes that the number of seats needed for a Commons majority is 326, but in practice it is slightly fewer at 320 once the Speaker, his three deputies and the seven Sinn Féin MPs who do not take their seats at Westminster are included.