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The Electoral Commission is seeking leave to appeal against a High Court ruling on spending by Vote Leave in the run-up to the EU referendum.

The election watchdog was judged earlier this month to have "misinterpreted" the legal definition of referendum expenses.

The judicial review was brought by campaign group The Good Law Project.

The group said the Electoral Commission had failed in its duty to regulate the referendum process.

An Electoral Commission spokesman said: "Today we are applying to the High Court for permission to appeal a judgement made last week which ruled on the interpretation of a point of law on campaign donations and expenditure.

"We are considering the implications of this judgement, including how it could impact on candidates, parties and non-party campaigners across all types of elections or referendums.

"The law must be as clear as possible in order to enable campaigners to fully and fairly participate in the democratic process.

"Should we obtain leave to appeal, this will inform any decision we make on whether to lodge an appeal against the judgement."

Mr Justice Leggatt, who heard the case with Mr Justice Green, said Vote Leave paid £620,000 to Canadian digital agency AggregateIQ at the request of another leave campaigner, Darren Grimes, in the days before the referendum.

This put Vote Leave over its £7m election spending limit by almost £500,000.

The Electoral Commission initially said there were "no reasonable grounds to suspect" the law on reporting expenses had been broken.

It changed its mind after the Good Law Project launched its case in October last year, starting an investigation into the spending of Vote Leave and Mr Grimes.

The watchdog concluded in July that both had incorrectly reported their spending.

Vote Leave was fined £61,000 and Mr Grimes was handed a £20,000 fine by the commission, which referred the matter to the Metropolitan Police.

Vote Leave says it was given incorrect advice by the Electoral Commission about the legality of funnelling money through Mr Grimes's group BeLeave, during the referendum campaign.

It has called on the watchdog to withdraw its fines or appeal against the High Court ruling.

The Good Law Project says the High Court ruling showed the watchdog had "unlawfully tilted the playing field in favour of Leave".

The Electoral Commission has said the High Court ruling was not about the advice it gave to Vote Leave.

"Our advice was generic and covered hypothetical scenarios," said the commission's chief executive Claire Bassett, following the ruling.

"At no point did we give any advice or discuss payments to Aggregate IQ."

Mr Justice Leggatt said there would be a further hearing to determine what orders the court should make as a result of its ruling.