(Bloomberg) — A U.K. intelligence watchdog has raised concerns over the threat of Russian interference in British elections, according to two people familiar with the findings of a secret report.While the investigation found no “smoking gun” evidence of Kremlin-sponsored interference in the past, the risk could still be there, the people said, speaking on condition of anonymity.Parliament’s Intelligence and Security Committee conducted an inquiry into the threat but Boris Johnson’s government has refused to release the findings, just as voters prepare to go to the polls in a general election next month. One of the report’s authors said the investigation would be potentially relevant to the current election debate.A row over the government’s refusal to publish the report dominated Parliament’s final day before the body was dissolved for the Dec. 12 election. The government insists that it needs more time to ensure that secret sources of information aren’t inadvertently revealed. People familiar with the report are equally insistent this work has already done.Britain’s government has in recent years repeatedly accused Russia of trying to meddle in other people’s elections, while insisting there’s no evidence it has interfered with any U.K. votes. It’s a sensitive issue given the divisions that have flowed in particular from the 2016 Brexit referendum.Fake NewsU.K. security officials are cagey even in private about Russian actions. The British voting process itself, involving paper ballots counted by hand in front of observers, is safe from hacking, but they acknowledge there are questions about fake news and interference in online discussions. In its report, the ISC examined the revelation that Russia-based Twitter accounts posted more than 45,000 messages about Brexit in just 48 hours during that campaign.Last year saw a more brutal example of Russian interference in Britain as the attempted poisoning of a spy in the city of Salisbury left a woman dead.ISC chairman Dominic Grieve on Tuesday accused ministers of sitting on the report. The Scottish National Party’s Stewart Hosie, who sits on the committee, said he was “at a loss” as why Johnson’s office had acted as it had.Labour’s foreign affairs spokeswoman Emily Thornberry has questioned the security vetting of Johnson’s senior adviser Dominic Cummings, who worked in Russia as a young man, after allegations over his links with Russian academics and intelligence officials.But one person familiar with the contents of the report said it did not mention Johnson or Cummings.Questions MockedOn Tuesday Thornberry’s questions were mocked by Foreign Secretary Dominic Raab, who told her in Parliament the insinuation “that No. 10 is somehow in the grip of a Kremlin mole is frankly ridiculous, even by the standards of the loony left.”A government official insisted the report contained nothing that ministers wished to hide and that officials had simply run out of time.But one of the committee members said the findings would have a potential impact on the election campaign debate, if ministers had not blocked publication of them.“I have no idea why Downing Street decided to sit on it, but it’s a sad day for government and Parliament,” Grieve said in an interview, declining to comment on the contents of the report. “I don’t know what impact it will have on the election — not zero impact, but probably not much.”Influence DisputedThe extent of Russian influence is disputed. According to a report by the Culture Committee, which examined disinformation, the U.K. “cannot state definitively that there was ‘no evidence of successful interference’ in our democratic process, as the term ‘successful’ is impossible to define in retrospect.” It added: “There is, however, strong evidence that points to hostile state actors influencing democratic processes.”However, discussing the EU referendum result. the Director General of MI5 Andrew Parker said last year he was “not aware of any information suggesting that the outcome was determined by any sort of interference.” That view was echoed by Ciaran Martin, the head of the National Cyber Security Centre, part of intelligence agency GCHQ, in multiple speeches.To contact the reporter on this story: Kitty Donaldson in London at email@example.comTo contact the editors responsible for this story: Tim Ross at firstname.lastname@example.org, Robert HuttonFor more articles like this, please visit us at bloomberg.com©2019 Bloomberg L.P.