A spreadsheet listing the addresses of 1,097 prominent public figures, including Elton John, was accidentally published online by the U.K. Cabinet Office | Kevin Winter/Getty Images for iHeartMedia UK privacy experts raise concerns over ‘catastrophic’ honors list leak Among the victims of the leak were Holocaust survivors, prominent politicians and the musician Elton John.

British privacy and intelligence experts have raised alarm bells after a government department in charge of the U.K.'s cybersecurity strategy accidentally published the addresses of prominent public figures and government officials.

A spreadsheet listing the addresses of 1,097 prominent public figures, including musician Elton John, politician Iain Duncan Smith, as well as top civil servants, academics and Holocaust survivors, was accidentally published online Friday by the U.K. Cabinet Office. The people in the list were recipients of New Year’s Honors, a British lifetime achievement award.

The leak could endanger the lives of police and government officials working on sensitive cases, experts warned on Sunday.

“A number of those receiving honours are employed in extremely sensitive positions in the police and intelligence agencies,” Richard Walton, the former head of counterterrorism at Scotland Yard, told the Sunday Times.

“The release of the private addresses of these individuals into the public domain will mean that a threat and risk assessment will need to be undertaken resulting in some having new private security measures introduced into their homes,” he added.

“This could be catastrophic,” prominent data rights lawyer Ravi Naik told the Guardian. “It is hard to put the information genie back in the bottle once it’s out. This quite sensitive data will spread like a virus and is extremely difficult to remedy.”

Silkie Carlo, the director of privacy non-profit Big Brother Watch said it was worrying to see the government lacking a "basic grip on data protection."

“It’s a farcical and inexcusable mistake, especially given the new Data Protection Act passed by the government last year — it clearly can’t stick by its rules,” Carlo told the Guardian.

Former leader of the Conservative Party Iain Duncan Smith also took aim at the government. "Ministers need to be asking some very serious questions of those involved about how this was allowed to happen and why no final checks were carried out before the document was published," he told the Sunday Times.

The Cabinet Office, which supports the work of the prime minister and is in charge of managing the country’s cybersecurity strategy, has apologized for the breach, and said it is investigating the cause. It says the list was online for around an hour.

The Information Commissioner's Office, which can fine organizations for data breaches, said it will be "making inquiries” into the breach.