Vote Leave has dropped its appeal against a £61,000 fine for electoral offences committed during the Brexit referendum.

The fine was imposed on the group, which was the lead campaigner for a leave vote, last year after the Electoral Commission concluded that it broke legal spending limits by donating hundreds of thousands of pounds to another leave campaigner, the then 22-year-old fashion student Darren Grimes, founder of BeLeave.

Vote Leave appealed against the fine, claiming that its donation to Grimes had been signed off by the commission. Supporters of the group suggested, without evidence, that commission staff were opposed to leaving the EU and were persecuting leave campaigners.

However, in a statement released on Friday afternoon, the Electoral Commission said Vote Leave had withdrawn its appeal. “We found that [Vote Leave] broke the electoral rules set out by parliament to ensure fairness, confidence and legitimacy at an electoral event,” it said.

Darren Grimes: the pro-Brexit student activist fined £20k Read more

“Serious offences such as these undermine public confidence in our system, and it is vital, therefore, that they are properly investigated and sanctioned. We have been advised that Vote Leave has paid its £61,000 fine and look forward to receiving the sum in full.”

Vote Leave said it had dropped the appeal for financial reasons. “Sadly, we now find ourselves in a position that we do not have the financial resources to carry forward this appeal, even though we are confident that we would have prevailed on the facts in court,” it said in a statement. “We have therefore regretfully decided to discontinue our appeal.”

Grimes, who was fined £20,000, said on Twitter that he would continue his personal appeal “until my last fucking penny”. He is crowdfunding his appeal and has raised almost £80,000 to cover the costs of the case.

Last week a judge sitting at the central London county court upheld the commission’s finding that four electoral offences had also been committed by a separate campaign Leave.EU.

However, the judge narrowed the scope of some of the findings. As a result, the £70,000 fine imposed by the commission may be reduced at a hearing next month.