Jo Swinson was once thought too timid. The Lib Dems Brexit pledge may now make her seem reckless

The bold stance reflects the new Remain versus Leave dividing line and means the Lib Dems no longer have to be ‘all things to all people’

When Jo Swinson became Liberal Democrat leader in July, some doubters in her own party worried that her weakness might prove to be that she is by instinct too cautious. They can’t accuse her of that now.

In her closing speech to the Lib Dem conference in Bournemouth today, Swinson reiterated her bold pledge to “stop Brexit” by revoking Article 50 “on day one.” With passion and confidence, she made the case for liberalism as a force whose time has come in the Brexit crisis, while tackling the criticism that she heads a single-issue party by highlighting the climate emergency, the economy and knife crime.

The central new policy offers the benefit of clarity, a welcome respite from Labour’s fuzziness on Brexit. It certainly passed the “will it get noticed?” test, giving a buoyant Lib Dem conference a higher media profile than it would otherwise have enjoyed. It is attractive because it is honest: while Labour offers voters a choice between its own Brexit deal and Remain in a referendum, the Lib Dems can now tell them: “what you see, and what you vote for, is what you get.”

The bold stance reflects the new dividing Remain versus Leave dividing line and means the Lib Dems no longer have to be “all things to all people”, with different messages in different parts of the country as they try to woo Tory and Labour voters. (They can now accuse Labour of doing precisely that on Brexit, while trumping Labour’s referendum pledge to Remainers).

But even with the Lib Dems, there is a catch. The full sentence in Swinson’s speech is: “we are crystal clear: a Lib Dem majority government will revoke Article 50 on day one.” While she is right to aim high in such an uncertain political landscape, even the most optimistic Lib Dems find it a bit of a stretch to see her becoming prime minister.

When the genuine sense of energy and excitement at their conference has passed, a more realistic scenario will surely re-emerge: the Lib Dems return to their temporarily eclipsed policy of a Final Say referendum, which they were the first party to promise.

They are winning new recruits from the two old parties but still have only 18 MPs. Labour has 247. For all Swinson’s refusal to prop up a Jeremy Corbyn (or Boris Johnson) government and portraying Corbyn as cut from the same populist, pro-Brexit cloth as Nigel Farage, the Lib Dems’ best hope of stopping Brexit will probably lie in supporting the Queen’s Speech of a minority Labour government that includes a referendum.

Her revoke pledge has echoes of Nick Clegg’s 2010 Lib Dem manifesto. It is remembered for its ill-fated pledge to abolish university fees, which the party then trebled to £9,000 a year during its coalition with the Tories. The broken promise became a millstone round Clegg’s neck. In fact, the manifesto pledged to phase out fees over six years. The joke at Westminster at the time was that they would finally be scrapped during the second term of a majority Lib Dem government.

Swinson deserves praise for promising what she really believes in. But will her full throttle revoke pledge really enhance the Lib Dems’ electoral prospects?

The calculation is that only about one in eight Lib Dem voters are Leavers, so the only way to expand the party’s base is to hoover up the Remain vote. There are hopes the crystal clear pledge will tip some Labour-held seats in Remainer land into the Lib Dem column. True, it might persuade some of the natural Labour voters who backed Swinson’s party at the European Parliament elections in May to stick with the party. But others, even those with doubts about Corbyn, will be tempted to return home, fearing that voting Lib Dem could split the anti-Tory vote in their constituency and allow the Tories to win it.

As one Lib Dem insider admitted: “The problem is that we start a long way behind in some Remain seats. Will voters there really think we can win them?” Brexit has changed much, but not the party’s credibility problem under our archaic first-past-the-post system.

Swinson is not only gambling that Johnson will not secure a deal or implement no-deal before an election. She also risks losing support in Tory-held seats, including some of her party’s best hopes in its former south-west stronghold. Overturning the 2016 referendum without holding another one will be a hard sell to many of the estimated 4 million Tory Remain voters, for whom the Lib Dems might otherwise be a natural home.

Swinson also left herself open to the charge of double standards: an election would be good enough to overturn a referendum on Brexit but not on Scottish independence if the SNP won a mandate for one.

Even some Remainers in other parties baulk at a revoke stance as anti-democratic, fearing that it would further polarise our politics rather than bring closure to Brexit as the Lib Dems hope. That is why MPs rejected it as a way to stop no-deal by 293 votes to 184 in March. As Caroline Lucas, the sole Green MP, said: “You can’t turn back the clock. Nor ignore the 17 million who voted Leave. This doesn’t strengthen our democracy. It further imperils it.”