By Estelle Shirbon
LONDON (Reuters) - A retired British politician sued the wife of the House of Commons Speaker for defamation on Thursday, accusing her of implying in a tweet that he was a pedophile guilty of sexually abusing boys living in a care home.
Alistair McAlpine, an associate of the late former Prime Minister Margaret Thatcher, is seeking damages from Sally Bercow in Britain's most high-profile Twitter defamation case to date.
Bercow tweeted "Why is Lord McAlpine trending? *Innocent face*" on November 4 last year, two days after a BBC report accused an unnamed "leading Conservative politician from the Thatcher years" of sexually abusing boys in the 1970s and 80s.
McAlpine was widely named on the Internet as the subject of the report, which the BBC later admitted was wrong. It paid 185,000 pounds ($281,700) in damages to McAlpine, who also received damages from others who had reported the story.
A trial at London's High Court to determine whether Bercow's tweet was defamatory began on Thursday morning. The judge is expected to reserve judgment to a later date.
If he rules that the tweet was defamatory, there will be a separate trial in July to determine the amount of damages Bercow should pay.
McAlpine's lawyer Edward Garnier, also a Conservative member of parliament, told the court Bercow's tweet was defamatory because many of her nearly 60,000 Twitter followers would have been aware of the media frenzy sparked by the BBC report.
"There was a prominent and salacious story in the media, and what was missing was the name of the abuser at its centre," Garnier said in a written argument.
"(Bercow's) tweet, by asking why he was 'trending' on Twitter combined with the coy sign-off of *innocent face*, identified (McAlpine) as the unnamed leading Conservative politician from the Thatcher years," Garnier said.
After it emerged that the BBC story was wrong and McAlpine was publicly vindicated, Bercow tweeted again on November 9: "Final on McAlpine: am VERY sorry for inadvertently fanning the flames. But I tweet as me, forgetting that to some of u I am Mrs bloody Speaker".
Bercow's husband John, as Speaker of the lower house of parliament, adjudicates the often noisy and fractious debates between Britain's rival parties who face each other across the floor of the House of Commons.
Sally Bercow's lawyer argued the tweet was not defamatory because it merely posed a question and made no statement of fact.
Bercow has frequently made the front pages of the British press. She took part in the reality TV program "Celebrity Big Brother" in 2011 and was widely criticized that year for posing wearing nothing but a bedsheet, with the House of Commons in the background, for a magazine interview.
(Editing by Sonya Hepinstall)