A would-be attacker who planned to kidnap, rape, and murder one of the UK’s top celebrities was given a life sentence with a minimum jail term of 15 years.

Gavin Plumb, 37, was last week found guilty of planning to “ambush” television presenter Holly Willoughby, 43, at her home, before taking her to a dungeon-type room.

He was caught after a US undercover police officer infiltrated an online group and forwarded Plumb’s posts to the FBI.

US law enforcement officers then handed the evidence to UK police, who raided Plumb’s home in Harlow, southeast England. They found an “abduction kit,” which included cable ties and chloroform.

Willoughby, a daytime television presenter described by judge Edward Murray as a “well-known and well-loved public figure,” said the case had had a “life-changing” impact, according to a summary of her victim impact statement read in court.

“It is clear, the prosecution submit,… that the extent of the shock and fear caused by this offending has been impossible to convey,” said prosecutor Alison Morgan.

Morgan also said the media had not reported the full extent of his plans as they were “so depraved and vile,” but the court was told that Plumb had intended to harm Willoughby’s husband and children.

Plumb, who has a string of previous convictions relating to kidnapping and false imprisonment, told the undercover police officer online that he planned to slit Willoughby’s throat as he tried to convince him to join in the plot, court heard.

His legal team said that he “worshipped and was obsessed” by Willoughby and was “devastated to be the cause of such pain to her.”

Nicola Rice, a specialist prosecutor with the Crown Prosecution Service, called Plumb “a dangerous man who plotted unspeakable violence against one of the nation’s most familiar faces.

“Despite his attempts to pass himself off as a harmless fantasist, the prosecution persuaded the jury that Plumb posed a very real threat,” she added.

In England and Wales, life imprisonment is a sentence that lasts until a prisoner dies, but in most cases the judge sets a minimum term, after which they become eligible for parole. (AFP)