A European Union flag flutters outside the Palace of Westminster, London, Britain, December 18, 2017. REUTERS/Toby Melville

LONDON (Reuters) - The main “Leave” group in Britain’s 2016 EU referendum may have broken electoral rules by over-spending during the campaign, according to a legal opinion published by a parliamentary committee on Friday.

The Vote Leave group may have dodged limits on spending by failing to declare expenditure worth 625,000 pounds ($892,000) to electoral authorities, the opinion said.

Vote Leave made a donation to another Brexit campaign group, BeLeave, that then channelled the money to a digital services firm, violating election rules because the groups worked together, the opinion published by the Digital, Culture, Media and Sport Committee said.

“We consider that there is a prima facie case that ... electoral offences were committed by Vote Leave in the EU referendum campaign,” the legal opinion prepared by the law firm Matrix Chambers said.

“These require urgent investigation so that consideration can be given to whether to refer the case to the Crown Prosecution Service for a decision on whether to prosecute,” the opinion added.

The Digital, Culture, Media and Sport Committee is investigating the spending of the main campaign groups in the EU referendum as part of an investigation into fake news.

A spokeswoman for the committee said the members of parliament did not commission the legal opinion and it was submitted as part of evidence.

Dominic Cummings, a former Vote Leave director, did not immediately respond to a request for comment.

Cummings has previously denied his group broke any rules, saying it had received permission from the Electoral Commission to make donations in the run-up to the referendum.