Since their introduction in 1979, elections to the European parliament in the UK have rarely been about Europe. They have often been seen by a third of voters who bother to take part as an opportunity for a free kick at the governing party.

The elections due to take place on 23 May will be different. They will go ahead unless Theresa May can persuade the Commons to endorse her Brexit deal or a version of it, which looks unlikely.

On the face of it, the contest has all the makings of a farce. If, for example, MPs passed a withdrawal agreement on 22 May, the elections could be cancelled on the final day of campaigning. Should the contest take place (at an estimated cost of £109m), the UK’s 73 MEPs would never take their seats if a Brexit deal were approved by 1 July, when the new parliament gathers in Strasbourg. Or they could serve for just weeks or months if MPs backed an agreement at a later stage.

It is no wonder that Ms May will strain every sinew to avoid these elections. Coming almost three years after the 2016 referendum, they would be a giant symbol of her failure.

Farage launches his new Brexit Party: in pictures Show all 10 1 /10 Farage launches his new Brexit Party: in pictures Farage launches his new Brexit Party: in pictures Nigel Farage speaks at the launch of his new Brexit Party's campaign for the European elections Reuters Farage launches his new Brexit Party: in pictures Brexit Party candidate Annunziata Rees-Mogg, sister of Conservative MP Jacob Rees-Mogg, speaks at the launch AFP/Getty Farage launches his new Brexit Party: in pictures A supporter waits for Farage to speak AFP/Getty Farage launches his new Brexit Party: in pictures Supporters wait for Farage to speak AFP/Getty Farage launches his new Brexit Party: in pictures Farage's socks Reuters Farage launches his new Brexit Party: in pictures Farage and prospective candidate Annunziata Rees-Mogg wait at the launch AFP/Getty Farage launches his new Brexit Party: in pictures Supporters listen as Farage speaks AFP/Getty Farage launches his new Brexit Party: in pictures Free T-shirts for all attendees AFP/Getty Farage launches his new Brexit Party: in pictures Posters on the seats for supporters of the Brexit Party AFP/Getty Farage launches his new Brexit Party: in pictures A safety sign is pictured AFP/Getty

Not surprisingly, opinion polls suggest the Conservatives will do badly. Since the original exit day of 29 March passed, Tory support has averaged 31 per cent, down eight points since last November. An Opinium poll for The Observer of those certain to vote in the Euro elections found that only 17 per cent would back the Tories, while 29 per cent would support Labour, 26 per cent pro-Remain parties (the Liberal Democrats, SNP, Greens and Change UK, also known as the Independent Group) and 25 per cent either Nigel Farage’s party or Ukip.

Clearly, Leave voters are deserting the Tories and are likely to express their anger at the failure to deliver Brexit by backing Mr Farage’s new Brexit Party or his old one, Ukip. The Tory hierarchy fears that many natural supporters who don’t switch to a “deliver Brexit” party will stay at home. Even some Tory MPs might support Mr Farage’s latest comeback act, while grassroots activists may work to rule or go on all-out strike.

The one in four people who voted Tory at the 2017 general election and backed Remain a year earlier are often forgotten in a debate dominated by the noisy Eurosceptics. Their votes are also up for grabs. They may be unimpressed that Ms May is only now belatedly reaching out to Labour for a consensus that might appeal to at least some of the ignored 48 per cent.

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Philip Hammond, the chancellor, was wrong to describe the Euro elections as “a pointless exercise” and say that “no one wants” to fight them. They may be inconvenient for his party, but it is in a mess of its own making.

While it will be difficult for the Tories and Labour to unite their parties behind a manifesto, the elections are an opportunity for pro- and anti-Brexit forces. The proportional representation system will ensure that every vote counts, unlike the archaic first-past-the-post method used at general elections.

Since the two main parties gobbled up 82 per cent of the votes between them in 2017, they have hardly proved worthy of such an endorsement. The Euro elections will provide a more up-to-date picture of the nation’s mood, and it would be refreshing if the smaller parties do well. Hopefully, the Electoral Commission will not get bogged down in bureaucracy and will allow the Independent Group to register as a party in time to field candidates.

Democracy does not stand still: people can change their minds at the next election. We would rather have a Final Say referendum but, in the meantime, the Euro elections will provide an important test of how opinion on Brexit has changed since 2016.