The Metropolitan Police spent £2 million looking into Carl Beech's allegations - made over the course of hours' worth of tearful interviews - that he had been sadistically raped and abused by famous Westminster figures in the 1970s and 1980s.
The 51-year-old former nurse made malicious and deceitful claims about men including 91-year-old Normandy veteran Field Marshal Lord Bramall, the late Lord Brittan and former Tory MP Harvey Proctor.
All three men had their homes searched by Metropolitan Police officers during the Operation Midland probe, which was set up in 2014 to look into the divorced father-of-one's allegations.
The force has come under widespread criticism for the investigation, which closed in 2016 without making a single arrest and was described by Mr Proctor as a "truly disgraceful chapter in the history of British policing".
Among Beech's allegations were claims that his step-father, an Army major, raped him and passed him on to generals to be tortured and sadistically abused at military bases by other establishment figures.
Those he named as supposed "abusers" included former prime minister Sir Edward Heath, late Labour MP Greville Janner, disgraced TV star Jimmy Savile, and security chiefs Sir Michael Hanley and Sir Maurice Oldfield, who were the heads of MI5 and MI6 respectively.
Jurors at Newcastle Crown Court saw through the lies of the school governor and NSPCC volunteer, and found him guilty of 12 counts of perverting the course of justice and one of fraud.
He was jailed for 18 years on Friday when he was sentenced for those offences, as well as charges of voyeurism and possession of indecent images which he had previously admitted.
Prosecutor Tony Badenoch QC had previously explained to the jury how Beech had showed "breathtaking hypocrisy" in accusing others of sex offences against children while he himself demonstrated an interest in pre-teen boys.
Over the course of the trial, which spanned more than two months, jurors heard how Beech spun officers lie after lie.
He claimed that the gang of men, who he referred to as "The Group", had run over and killed a boy named Scott in front of him - but prosecutors said that the child described had in fact never existed.
The fraudster gave false hope to the family of Martin Allen, who went missing in 1979 at the age of 15, by saying that he had seen a youngster matching his description raped and strangled in front of him.
After Operation Midland was closed, Beech fled to Sweden at a time when the Crown Prosecution Service were considering whether to bring charges against him, buying two properties there and trying to evade justice by using false identities.
He was extradited back to the UK to face charges in October last year.
His lies were at one stage wrongly described as "credible and true" by a senior detective.
Metropolitan Police Deputy Commissioner Sir Stephen House said that officers in the case had worked in good faith, and that an "internal debrief" would take place following Beech's conviction to identify whether lessons could be learned.
Labour's deputy leader Tom Watson has been criticised for meeting with Beech in 2014, but the politician said he had simply told him the allegations would be taken seriously, saying in a statement: "It was not my role to judge whether victims' stories were true."