(Bloomberg) -- Vote Leave, the official pro-Brexit campaign in the U.K. referendum on European Union membership, was fined for breaking electoral laws -- a verdict that is likely to further fuel calls for a second ballot.

Vote Leave breached spending limits and violated rules on working jointly with other groups during the 2016 campaign, the Electoral Commission said, adding that the case has been referred to the Metropolitan Police. Speaker of the House of Commons John Bercow granted an opposition Labour Party request for the government to make a statement to Parliament on the decision.

“The prime minister is absolutely clear that this was the largest democratic event in our country,” her spokesman, James Slack, told reporters in London on Tuesday. “This was a legitimate democratic exercise in which the public delivered its verdict and we getting on with implementing it.”

“It would not be appropriate for the government to comment on ongoing police investigations,” said Chloe Smith, Cabinet Office minister, in response to an urgent question in Parliament.

The verdict comes at a time when a growing number of lawmakers are openly discussing the need for a second referendum on Brexit to end the quagmire in Parliament, where Prime Minister Theresa May is caught between the various factions in her Conservative Party trying to shape Britain’s departure agreement with the EU. Former Education secretary Justine Greening made the case over the weekend for a second vote, the most senior Tory yet to do so.

‘Escape This Mess’

Tom Brake, Brexit spokesman for the pro-EU Liberal Democrats, said the findings “strengthen the need for a vote on the deal and an opportunity for the country to escape this mess.”

Vote Leave worked under a “common plan” with BeLeave, another campaign group, spending more than 675,000 pounds ($895,000) on work from data firm Aggregate IQ, the commission said. That helped push Vote Leave over the 7 million-pound spending cap for the vote, and breached rules banning joint work. Both Vote Leave and BeLeave deny wrongdoing.

“These are serious breaches of the laws put in place by Parliament to ensure fairness and transparency at elections and referendums,” the commission’s legal counsel, Bob Posner, said in the statement. “We found substantial evidence that the two groups worked to a common plan, did not declare their joint working and did not adhere to the legal spending limits,” Posner said.

Posner said Vote Leave resisted the probe “from the start” and refused to cooperate. Vote Leave was fined 61,000 pounds, while Darren Grimes, the founder of BeLeave was fined 20,000 pounds. A third group, Veterans for Britain, was fined 250 pounds. Grimes and David Halsall of Vote Leave were referred to the police in relation to false declarations of campaign spending.

Vote Leave said in an emailed statement the commission’s report contains “a number of false accusations and incorrect assertions.” Grimes said in a statement on Twitter that he had done “nothing wrong.”

“It is astonishing that nobody from Vote Leave has been interviewed by the Commission in the production of this report, nor indeed at any point in the past two years, despite Vote Leave repeatedly making it clear they are willing to do so,” Vote Leave said, adding that it will “consider the options available to us.”

To contact the reporter on this story: Alex Morales in London at amorales2@bloomberg.net

To contact the editors responsible for this story: Flavia Krause-Jackson at fjackson@bloomberg.net, Stuart Biggs

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