It will take more than a milkshake to stop Nigel Farage — but he should be frank about his funding

There can be no excuse for “milkshaking” Nigel Farage. Throwing anything — eggs, custard pies, milkshakes — at a politician is an assault and should be prosecuted as such. Even though the Brexit Party leader’s security is said to cost thousands of pounds a day, he could not be adequately protected while on the stump. What if the liquid thrown at him had not been a milky drink, but acid?

It will take more than a milkshake, though, to stop Farage. Having gone from zero to hero twice in his career, first with Ukip and now with the Brexit Party, he has already delivered one shock to the British political system and is now threatening to administer another.

It’s quite an achievement. But Farage has questions to answer about how both his party and his lifestyle have been funded, according to Gordon Brown. The former Labour Prime Minister has accused him of accepting “undeclared, unreported, untraceable payments”, perhaps from foreign sources. The Electoral Commission has opened an investigation into the Brexit Party, just three days before Thursday’s election, despite protests from Farage about “an establishment stitch-up”.

The Brexit Party insists that it abides by the rules. Its chairman, Richard Tice (who is also the co-founder of Leave.EU), says it has paid for its highly professional European election campaign mainly from £25 donations by more than 100,000 “supporters”, using PayPal. One large gift of £200,000 by Jeremy Hosking, a former Conservative Party and Leave campaign donor, has been declared. The party says that names of other larger donors would be published by the Electoral Commission in due course.

If this is true, then the Brexit Party has nothing to hide. The Electoral Commission is visiting its offices, not on a fishing expedition, but with the sole purpose of ascertaining whether the party is able to match small donations with names on the electoral roll, as the law requires. This is not a “shakedown”, but a regulatory body doing its job.

What of Farage’s own finances? Arron Banks, the other founder of Leave.EU, says that he spent £450,000 of his own fortune supporting Farage’s lifestyle, including security, during the two years after the 2016 EU Referendum. It is unclear whether this money was officially declared, despite the fact that the Brexit Party leader is still an MEP. There is no reason to suppose that the Electoral Commission will include Farage’s personal finances in their investigation, but he is accountable to the European Parliament and, like everyone else, to HM Revenue and Customs.

It is neither unusual nor illegal for politicians to receive support when they leave office. David Cameron was given free accommodation for many months after resigning as Prime Minister, for example. But transparency is one of the pillars of democracy, and populists must play by the same rules as everyone else. Austria’s ruling coalition has just collapsed after the Vice-Chancellor and populist leader, Heinz-Christian Strache, was caught on video accepting a bribe from a fake Russian donor. The affair has highlighted the murky finances of Europe’s populist parties, some of which are pro-Russian.

Straightforward bribery scandals like the one now playing out in Vienna are the exception rather than the rule. Such questions about party funding are usually complex and hence unlikely to affect the impact of the populist wave on Thursday’s European elections. Financial scandals have blighted the careers many of postwar Europe’s political giants: Helmut Kohl, Silvio Berlusconi, Jacques Chirac, to name only a few.

Here in Britain, however, we pride ourselves on keeping our politics clean and transparent. Part of the Brexit Party’s appeal has been its clarity of purpose: it does what it says on the tin. In Britain we also have a free press whose instinct, when faced with evasive answers to legitimate questions, is to follow the money. Nigel Farage would be wise to bluster less and co-operate more.