Can the Liberal Democrats turn momentum into votes?

It seems the sky is the limit for the Liberal Democrats at the moment, as unbridled optimism sweeps over the party’s annual gathering.

After years in the wilderness, the Lib Dems are on the up and they are clearly feeling jubilant.​

Chuka Umunna, one of the party’s recent converts, claimed it could win 200 seats in the next election, while Jo Swinson, the Liberal Democrat leader, said she was aiming for a slightly more moderate 100 seats.

The party’s ranks were bolstered by former Tory MP Sam Gyimah on Saturday, who became the sixth MP to defect to the Liberal Democrats in recent months.

He joins ex-Conservatives Sarah Wollaston and Phillip Lee, as well as former Labour MPs Luciana Berger, Umunna and Angela Smith in moving over to Jo Swinson’s newly energised party.

But it remains to be seen whether this momentum can be turned into votes at an early general election.

Recent opinion polls tend to put the Lib Dems in third place behind the Tories and Labour, with the latest survey by Opinium putting the party on 16 per cent.

If the party wants to make serious gains it will need to consolidate the Remain vote, which has been fragmented since the referendum.

The Lib Dems’ unashamed support for Remain has contrasted positively with Labour’s equivocation. But Jeremy Corbyn’s party is now shifting towards a more pro-EU position.

So Swinson has gone even harder, telling the party faithful in Bournemouth that the Lib Dems would revoke Article 50 without a referendum if she was in Downing Street.

The move has caused fury among Brexiteers, who deem it undemocratic, as well as ripples of concern among advocates for a Final Say referendum.

But Swinson is gambling this will play well for her Europhile base. The Opinium poll found 55 per cent of Remain voters supported cancelling Brexit, and only 26 per cent support extending the Brexit negotiations and putting a revised deal to a public vote.

The pledge is designed to offer a distinctive message from Labour, in advance of its annual conference in Brighton this weekend.

Labour has already shifted towards supporting a referendum on any deal – and pro-EU activists will be piling the pressure on Corbyn to commit to campaigning for Remain.

The problem for the Lib Dems will be transforming the energy and optimism into Westminster seats.

Veteran pollster Sir John Curtice said there were only 22 constituencies where the Lib Dems came within 25 points of the winning candidate in 2017, which he himself describes as a “generous definition” of a marginal seat.

Of these seats, plenty were in Leave areas and would involve taking on the Tories, who are starting to hoover up the Brexit Party vote.

The Lib Dems and Labour could end up scrabbling over the same voters in pro-EU areas – leaving the way clear for the Conservatives.

An upcoming election will undoubtedly be a Brexit election, but the Lib Dems will want to think carefully about what else they stand for, if they want to win big.