Boris Johnson is facing a legal challenge over Vote Leave's £350 million Brexit bus claim

While politicians making false promises is hardly news, one untruth told during the Brexit referendum was particularly hard to swallow – and hard to miss.

Of course we’re talking about Boris Johnson’s infamous claim that the UK sends £350 million to the EU every week, which in a post-Brexit utopia would be spent on the NHS.

Just in case we missed the statistic in their speeches, he and the Vote Leave campaign proceeded to plaster it to the side of a big, red coach dubbed the 'Brexit Battle Bus'.

While the figure was widely debunked – just days after the campaign, prominent Brexiteers like Nigel Farage admitted it was "a mistake" – Mr Johnson ratcheted up his defence, telling The Guardian in January 2018 that the sum was too low:

There was an error on the side of the bus. We grossly underestimated the sum over which we would be able to take back control.

Fast-forward to 2019 and a "true hero" has raised more than £400,000 to take Mr Johnson to court for “abusing public trust”.

If successful, the first-of-its-kind case could change the way politicians are held accountable for their claims while in office.

Marcus Ball, a 29-year-old private prosecutor, and his team of five legal representatives, will appear today at Westminster Magistrates Court under the name Brexit Justice.

The team hope the case could develop into criminal charges for misconduct in a public office, which carries a maximum sentence of life in jail.

Mr Ball said in a statement:

I believe that when politicians lie, democracy dies.

If a company director lies to shareholders about financial matters they can be prosecuted. If a self employed person lies to HMRC about their spending or income they can be prosecuted.

If a member of the public lies to the police about an ongoing investigation they can be prosecuted.

"This is because society and public trust cannot function based upon false information. So, why shouldn’t a politician be prosecuted for abusing public trust by lying about public spending figures?"

Mr Ball believes a successful case could have a knock-on effect in countries like Canada, New Zealand, India and Australia.

No politician has ever been convicted over false claims before.

But in 2014, PC Keith Wallis was convicted of misconduct in a public office after he lied to his MP and colleagues over the 2012 "Plebgate" scandal involving the Tory chief whip Andrew Mitchell.

He was sentenced to one year in prison.

The Brexit Justice team will appear in court at 2pm today (Tuesday 14 May), while Johnson has not been summoned by a judge.

Many were keen to voice their support.

indy100 has contacted Boris Johnson's office for comment.

More: Final Say: 11 things politicians have said about Brexit which look a little naive now