The cases against prominent pro-Brexit campaigners Darren Grimes and Alan Halsall have been dropped, the Metropolitan Police has confirmed.

BeLeave founder Darren Grimes was fined in 2018 after being accused of breaching spending rules during the European Union referendum campaign almost four years ago.

He was ordered to pay £20,000 by the Electoral Commission, the body responsible for regulating political parties, members and campaigners.

But Mr Grimes won an appeal against the fine in July, having crowdfunded to raise £93,956 to contest it in court.

And the Met Police have now confirmed, 10 months on from Judge Marc Dight’s decision, that no further action will be taken against Vote Leave and BeLeave following investigations into allegations of false declarations of campaign spending.

Once again the Electoral Commission has been found to be part of the mob, a quango out of control that isn’t policing elections so much as punishing Leavers who have the temerity to win them

A spokesman for the Leave campaigners said: “The Metropolitan Police has written to Vote Leave board member Alan Halsall and BeLeave founder Darren Grimes to confirm that it will not be acting on allegations made against them by the Electoral Commission and various Remain campaigners.

“This marks the end of a two-year ordeal for both individuals.”

Mr Grimes, 26, said the development called into question whether the Electoral Commission was “fit for purpose”.

He had insisted since the allegations were first made that he was “completely innocent” of making false declarations in relation to a £680,000 donation to his youth-focused BeLeave group from the main Vote Leave campaign.

The spending took Vote Leave over its £7 million legal spending limit by almost £500,000.

While Mr Grimes successfully contested the fine, Vote Leave has since paid in full a £61,000 fine related to the incident after opting to drop its own appeal, the PA news agency understands.

In a statement, Mr Grimes, a former fashion student originally from County Durham, said: “The Metropolitan Police has found, after investigation and consultation with the Crown Prosecution Service, that there is no case to be answered.

“Once again the Electoral Commission has been found to be part of the mob, a quango out of control that isn’t policing elections so much as punishing Leavers who have the temerity to win them.

“My ordeal at the hands of the kangaroo court that is the Electoral Commission is now over, but questions must now be asked of whether that body is fit for purpose.”

He also took aim at Observer journalist Carole Cadwalladr, claiming her “conspiracy theories have once again been found to be completely untrue, but have helped us expose the Electoral Commission”.

Mr Halsall, the responsible person for Vote Leave, said he was “delighted to have been exonerated” and thanked the police for their “professional” investigation.

“I was very disappointed that my colleagues at Vote Leave and myself were never given the opportunity of making our case in person to the Electoral Commission before being fined and reported to the police,” he added.

“It seems a rather unusual way of conducting an inquiry into such matters that only the so-called whistleblowers who made these allegations are interviewed by the regulator.”

The Electoral Commission denied it had not take evidence from the accused, stating that Vote Leave had “multiple opportunities to put across its side”.

A spokesman for the Met said an investigation into the Electoral Commission’s allegations against Vote Leave and BeLeave, submitted on July 17 2018, was handed over in October to the Crown Prosecution Service (CPS).

“On Tuesday, March 3 preliminary advice was received from the CPS,” said the force spokesman.

“This advice has now been duly considered and no further action will be taken.”

A spokesman for the Electoral Commission said: “We referred this matter to the police so that offences that lie outside of the commission’s remit could be properly investigated.

“We are pleased that the Met Police have taken the matter seriously.

“The matters we asked the police to consider were separate and further offences to those we found Vote Leave had committed, for which we imposed fines, which they have paid.

“When asking the police, as the proper authority to consider those matters, we did so in order that the evidence can be properly and fairly considered.”