LONDON, England (CNN) -- The office of the British prime minister has apologized after e-mails sent by one of Gordon Brown's senior officials reportedly smeared political opponents, British media said Saturday.
The details of the leaked e-mails are another embarrassment for PM Gordon Brown.
The e-mails, which made a number of innuendo-laden suggestions about the private lives of politicians, including Conservative Party leader David Cameron, ended up in the hands of a well known political blogger, the Telegraph reported.
They were sent in January from a supposedly secure Downing Street account by special adviser Damian McBride to former Labour party adviser Derek Draper, The Daily Mail added.
However, in another embarrassing security leak for the British government, they instead ended up with Paul Staines, who writes under the name "Guido Fawkes."
Staines, who refused to comment about how he received the e-mails, claimed that he was not politically motivated but that "Labour was a natural target because of its 12 years in power," the Daily Mail said.
A Downing Street spokesman said the messages were "juvenile and inappropriate," the BBC reported. He added that "neither the prime minister nor anybody else in Downing Street, except the author, knew anything about any of these private e-mails."
Shadow Home Secretary Chris Grayling described the e-mail leak as "ludicrous." He told BBC Radio 4's Today program Saturday: "We are in the middle of the biggest economic crisis for half a century. Is this really the best Downing Street can do?"
McBride, an adviser at Downing Street, was removed from his post dealing with the media following the resignation of former Transport minister Ruth Kelly in September last year. He remained with the government in a different role.
The latest security breach follows the resignation last week of a senior anti-terror policeman, after he was photographed arriving at Downing Street holding a document revealing details of a secret terror raid.