The constituency of St Ives, which Boris Johnson visited on Wednesday, is one of the Conservative Party’s most vulnerable seats at this election.
Tory candidate Derek Thomas is defending a majority of just 312.
A swing of 0.3% would see the UK’s most south-westerly constituency change hands to the Liberal Democrats.
St Ives has been a marginal seat at every general election this decade – and always a two-horse race between the Tories and Lib Dems.
Mr Thomas won the seat from the Lib Dems in 2015, achieving a majority of 2,469.
Two years later the Lib Dems came very close to defeating him, taking 42.6% of the vote to the Tories’ 43.2%.
The Lib Dem candidate on that occasion was Andrew George, who had lost St Ives to Mr Thomas in 2015.
Now Mr George is making another attempt to retake the seat.
He is well known in the area, having represented St Ives for the Lib Dems continuously from 1997 to 2015.
If the Lib Dems manage to attract a decent portion of the Labour vote in the constituency – 14% at the 2017 election – it could be enough to put Andrew George back into office.
Only three candidates stood in St Ives in the 2017 election. This time there are six: Conservative, Liberal Democrat, Labour, Green, Liberal and the Common People.