A glance at the top target seats for the Lib Dems quickly demonstrates how much of a challenge Jo Swinson’s party faces in the forthcoming general election. There are only four that can be taken on a slim 1% swing – including Fife North East – where the party finished just two votes behind the SNP’s Stephen Gethins.

Capturing the 10th most winnable seat – Lewes, in Sussex – would require a swing of 5.1%, however, while a 10% swing to the Lib Dems from all parties would only yield 18 seats across the UK. By contrast, the Conservatives can gain 19 seats on a 1% swing from all parties, and Labour, a handful more, at 22.

The second complicating factor for the party is Brexit. Its position as unambiguously pro-remain – its promise is to revoke Article 50 – means that it struggles to attract leave voters who are in the majority in some of the seats that it wants to gain, particularly in the south-west of England.

Its number seven target is Devon North, where the party needs a 3.9% swing to overturn a 4,332 majority. But it is estimated that 57% of the constituency voted leave in the 2016 referendum, making the task harder unless it proves possible to squeeze the Labour vote there.

John Curtice, a professor of politics at Strathclyde University, says the Lib Dems “are now the obverse of the Brexit party” with all the increase in vote share the party has received since the 2017 election coming from remain supporters.

As a result, he says, some pro-remain seats in and around London are starting to look like “home bankers” – such as Richmond Park (majority 45) and St. Albans (majority 6,109) where the party is chasing the Conservatives. However, others such as North Devon, and also North Cornwall (Con majority 7,200) and St Ives (Con majority 312) will be much more difficult, Curtice added.

For the Lib Dems to make inroads and avoid being squeezed, their task is to try and dramatically change the narrative – which the party is trying to do by putting highly selective polling information on its campaign leaflets in individual seats in an attempt to get voters to rethink.

This may prove possible in some cases, most notably in Finchley and Golders Green, where Luciana Berger, a former Labour MP, hopes to come from a distant fourth to snatch the seat by focusing her campaign on antisemitism in a constituency with a significant proportion of Jewish voters.

Luciana Berger is contesting the Finchley and Golders Green seat on a campaign against antisemitism. Photograph: Leon Neal/Getty Images

It is far more challenging to do so nationally however. The party has tried, by portraying its leader, Jo Swinson, as a potential prime minister, although this is an unlikely possibility, given its position third in the polls.

This attempted prime ministerial portrayal also explains why the Lib Dems are so unhappy about being squeezed out of the first TV debate: a head to head between Boris Johnson and Jeremy Corbyn, and why the two main parties are so keen to do so.

Current polling suggests that the Lib Dems will do better than in 2017, when the party secured a dismal 7.4% and only picked up 12 seats. But the Guardian’s poll tracker shows that it will come under intense pressure from Labour, now ahead among remain voters, and that its national share is currently only 16%.

All in all, the party will do exceptionally well to end up with 30 seats, and in fact, faces a battle to better the 20 it held at the conclusion of the last parliament, boosted by defections from both the Conservatives and Labour.