This analysis looks only at specific constituency visits, excluding set-piece speeches such as campaign launches and other events such as the two victory rallies Labour held for its wins in metro mayor elections. For Labour, these events have also predominantly taken place in safe Labour areas like Manchester and Liverpool, or Tuesday's manifesto launch in Bradford West.

Despite being behind in the polls, Corbyn's visits have followed a predominantly offensive strategy – similar to May's – focusing on seats Labour would be hoping to gain on their way to a majority, rather than defending constituencies they are at serious risk of losing.

Corbyn has visited 21 non-Labour-held seats, while May has visited 22 seats the Conservatives are targeting.

With just a few exceptions, May's visits to target seats have focused on Labour-held constituencies (trips to Scotland and Northern Ireland being the only exceptions).



Corbyn, likewise, has focused on Conservative-held seats; he visited his first seat held by any other party on Tuesday, the Liberal Democrat-held Leeds North West.



Leaders' visits can have an positive effect on the party's vote share, according to a study that examined the 2010 general election. It found that visits from both David Cameron and Nick Clegg helped increase their parties' vote share in those seats by 1.2% and 1.5% respectively, compared to non-visited seats. Gordon Brown's visits increased the Labour vote slightly, but not enough to be considered significant.

The YouGov polling data released on Monday does offer a possible rationale for Corbyn's lack of defensive visits to key marginals. It suggested that voters' impression of Labour in marginal seats improved when questions prompted them to think about their local area and their sitting MP rather than about the national campaign – implying that a visit from the national party leader might not necessarily be beneficial to Labour's vote.

A spokesperson for Jeremy Corbyn told BuzzFeed News: "We are campaigning to win in every seat in the country to form a Labour government that will transform Britain for the many not the few."