FILE PHOTO: Britain's Minister of State for Security and Deputy for EU Exit and No Deal Preparation Brandon Lewis is seen outside Downing Street in London, Britain October 24, 2019. REUTERS/Toby Melville

LONDON (Reuters) - The British government will publish a parliamentary report examining alleged Russian meddling in British politics after the country’s Dec. 12 election, security minister Brandon Lewis said on Sunday.

Opponents have accused the government of sitting on the report by parliament’s Intelligence and Security Committee (ISC), which has been cleared by the security services, because it might contain embarrassing revelations about Prime Minister Boris Johnson and his party.

Lewis told Sky News the report could not be published during the so-called “purdah” period which sets rules on government announcements during an election campaign.

“We want to make sure, particularly where national security is involved, we go through that process properly and thoroughly,” he said. “We can’t publish things during the general election ... but after the general election that report will be published.”

Last week the government had said the report had not been published because of necessary procedure whereby vetting it would take several weeks.

Britain has accused Russia of meddling or trying to interfere in western elections, accusations denied by Moscow. The ISC was examining allegations of Russian activity aimed at the United Kingdom, including in the 2016 referendum on EU membership, when Johnson was a leading campaigner to leave.

The Sunday Times said the report concluded Russian interference may have had an impact on the Brexit referendum but the effect was “unquantifiable”.