The main party leaders have been criss-crossing the country for nearly three weeks, but there is one type of constituency they have yet to visit on the campaign: a Liberal Democrat seat.

This is just as true for Lib Dem leader Jo Swinson as for Boris Johnson and Jeremy Corbyn.

The fact that all three have yet to make a campaign stop in a Lib Dem seat reflects the lopsided battleground of this year’s election.

The race for Number 10 will be won and lost mainly in constituencies that are contests between the Tories and Labour.

Neither of these parties has much chance of taking seats from the Lib Dems.

POLITICS Election Visits
(PA Graphics)

One reason is there are hardly any Lib Dem seats for them to take.

Another is that many of the seats the Lib Dems are defending are in areas that voted strongly Remain in the 2016 EU referendum, which puts them pretty much out of reach of the Conservatives.

Ms Swinson has yet to pay a campaign visit to a single seat her party is defending, which says a lot about her expectations in this election.

Instead she has spent her time mostly visiting Conservative and Labour seats that would need a big swing to be gained by the Lib Dems.

She has visited just two marginal seats on her party’s target list: Fife North East (being defended by the SNP) and St Albans (Conservative).

By contrast, Mr Corbyn has visited 13 Tory-held seats, 10 of which are marginal enough to fall to Labour on a swing of 5% or below – including the ultra-marginal seats of Pudsey (0.31%), Telford (0.81%) and Milton Keynes South (1.34%)

Labour leader Jeremy Corbyn on board the Labour battle bus (Jacob King/PA)
Labour leader Jeremy Corbyn on board the Labour battle bus (Jacob King/PA)

He has also visited 10 Labour-held seats, five of which are Conservative targets.

Mr Johnson has made fewer campaign visits than his Labour counterpart, but has still clocked up 12 Conservative-held seats and nine Labour-held seats, including two that would fall to the Tories on a swing of under 1%: Ashfield (0.44%) and Stockton South (0.82%).

Unlike the Labour and Lib Dem leaders, Mr Johnson has yet to go campaigning in an SNP-held constituency.

But he is the only leader to have travelled to all four nations of the UK.

Boris Johnson by the Conservative Party battle bus in Middleton, Greater Manchester (Stefan Rousseau/PA)
Boris Johnson by the Conservative Party battle bus in Middleton, Greater Manchester (Stefan Rousseau/PA)

Mr Corbyn has visited 31 seats, Mr Johnson 23 and Ms Swinson 12.

There is one constituency to which all three leaders have paid a visit: Doncaster North, a safe Labour seat, but the location of some of the worst damage in the recent floods.