An online "troll" who sent a threatening email to Conservative MP Louise Mensch received a suspended sentence Monday and was banned from contacting a string of well-known figures from Alan Sugar to CIA chief David Petraeus.

Frank Zimmerman, 60, was handed a 26-week prison sentence suspended for two years over the email sent to the Corby lawmaker.

He was also given a restraining order barring him from contact with a string of public figures and ordered to pay £300 costs at Cheltenham Magistrates' Court.

As well as Mensch, the restraining order listed Alan Sugar, the businessman and star of The Apprentice, former British army chief General Sir Mike Jackson, CIA director David Petraeus and Independent newspaper columnist Terence Blacker.

White-haired, bearded Zimmerman, who lives in Gloucester and says he suffers from agoraphobia -- a fear of public spaces -- is also banned from contacting Mensch's husband and ex-husband.

Mensch, 40, called in police and arranged security for her family after receiving the email from Zimmerman, which referred to the novel "Sophie's Choice", by William Styron, in which a woman must decide which of her children to save from death at the hands of the Nazis.

Along with a string of obscenities, the email, sent in August last year, read: "We are inside your computer and all your phones, everywhere ... and inside your homes.

"So get off Twitter.

"We have sent a camera crew to photograph you and your kids... You now have a Sophie's Choice. Which kid is to go? One will."

Mensch has nearly 60,000 followers on Twitter and regularly uses the microblogging site to communicate with members of the public.

Zimmerman was charged with an offence of sending by public communication network an offensive, indecent, obscene, menacing message or matter, after police traced the email to the IP address of his home computer.

He denied the offence, blaming hackers for sending the message, and his lawyer said Monday he was considering an appeal.

But district judge Martin Brown told him: "These were ugly, unpleasant and serious remarks to the complainant by email. Quite understandably they caused her great concern."

Zimmerman was taken to court by police after missing his originally scheduled sentencing hearing last week.

He was also handed a four-week suspended sentence for breach of bail, which was to run concurrently with his sentence for the internet crime.

[Conservative MP Louise Mensch arrives at the state opening of parliament in May. AFP Photo/Stefan Wermuth]