Boris Johnson will not face court over allegations of misconduct in a public office after winning a High Court appeal.
The case related to claims he made during the Brexit referendum that the European Union receives £350 million a week from the UK.
It was brought against Mr Johnson by campaigner Marcus Ball, who said he had spent three years of his life working on the case.
Ahead of the ruling, Mr Ball said: "Somebody who was doing this to create a stunt would not act like that."
He crowdfunded more than £300,000 to bring the prosecution.
Mr Johnson’s lawyers told the court the judge who issued the summons “erred in law” when reaching her decision.
They also argued the attempt to prosecute the Conservative leadership frontrunner is the culmination of a “politically-driven process”.
Adrian Darbishire QC, for Mr Johnson, said: “The only rational conclusion which could be reached was that the prosecution was politically motivated and, therefore, vexatious.”
He said Mr Johnson “doing something naughty” as part of the Vote Leave campaign was not an abuse of state power.
"Public debate about the accuracy or otherwise of the £350m continues to this day,” he said.
Jason Coppel QC, for Mr Ball, said “The entirely proper motivation for the prosecution is to hold to account a high-profile politician”.
He said Mr Johnson’s statements were false and “he knew them to be false”.
He added: “that's the misconduct that is alleged against him”.
Mr Johnson was not required to attend the hearing.
His spokesman said he would not be commenting on the case.