A man who made a series of “heinous” false allegations that prompted a multimillion-pound police investigation into an alleged VIP paedophile ring in Westminster fled to Sweden when his claims unravelled, a court has heard.

Carl Beech, previously referred to by police as “Nick”, is accused of lying when he claimed he was among victims of an alleged group of establishment figures including senior men in politics, the military and the intelligence services who raped, kidnapped and murdered boys in the late 1970s and early 80s.

Beech, 51, is on trial at Newcastle crown court where he faces 12 counts of perverting the course of justice from December 2012 to March 2016 and one count of fraud over a criminal compensation payout he pocketed.

The charges, which he denies, include that he made a false allegation of witnessing the murder of a child by the former Conservative MP Harvey Proctor. Beech, who worked for the Care Quality Commission health watchdog, is also alleged to have lied about claiming to have witnessed the murder of two other children.

Others he accused of abuse included the former prime minister Edward Heath, former home secretary Leon Brittan, field marshal Lord Bramall, the former Labour MP Greville Janner, television star Jimmy Savile and his late stepfather, major Raymond Beech.

Bramall’s wife died without knowing her husband was to face no further action, the court was told. Brittan died with the allegations hanging over him.

Beech also accused the diplomat Peter Hayman, the former head of MI5 Michael Hanley and the former MI6 chief Maurice Oldfield of being abusers. The offences were alleged to have taken place in locations including Dolphin Square, the Carlton Club and Elm Guesthouse in London, Heath’s yacht, military bases and London zoo. He claimed he was ferried from school by a driver to the “parties”, where there were seven or eight boys and 10 to 15 men.

Beech’s allegations led to a £2m Scotland Yard inquiry, Operation Midland, being set up. It shut in 2016, after which Northumbria police were appointed to investigate Beech and subsequently raided his Gloucester home.

Police found “a number of important claims” he made were “probably false”, the court heard. Opening the prosecution’s case on Tuesday, Tony Badenoch QC told the jury: “He had lied about the content of these allegations, taken active steps to embellish a false story and then cover his tracks when challenged. He made no response … when he was asked to account for this by Northumbria police and, ultimately … he took the only option that was really available to him: he fled the country and he lived overseas as a fugitive.

“That was until a specialist fugitive unit in Sweden worked closely with Northumbria police and the National Crime Agency to secure his arrest on a European arrest warrant executed overseas. He was then extradited back to this country to face these charges.”

The court heard that a Metropolitan police officer had described the allegations as “credible and true” in November 2014 when Scotland Yard launched its investigation. Beech was given the pseudonym Nick as he was afforded anonymity as a complainant of sexual abuse, the court heard.

Badenoch told jurors: “The allegations when investigated in this way have led to the conclusion that they are in fact ‘incredible and untrue’. They were and are entirely false allegations made by ‘Nick’.

“In his 40s, when he was a middle-aged man, Carl Beech claimed that when he was a young schoolboy he had witnessed no less than three child killings, and was subjected to rape, torture, and sexual abuse by literally dozens of powerful men, in politics, the armed forces, intelligence services and in showbusiness, at locations ranging four counties, the coast of England on the south coast, and all over London. He had been taken out of school once a week for this to occur. That is an extraordinary claim and it is also untrue.

“They are without question the most heinous allegations it is possible to make against somebody. To accuse a person of being a child murderer, rapist, sadist, torturer and abuser.”

The court was told that Beech had informed Scotland Yard about three alleged child murders, including of his friend Scott who he claimed was killed after being run over by members of the abuse ring. Beech said the killing was a result of him befriending Scott in defiance of the abusers’ orders.

Beech claimed he had been told not to befriend the pupil, whom he knew from primary school, but he defied them. He added: “They warned me. I was selfish, I didn’t listen to them because I wanted a friend. I didn’t understand what the consequences might be. He died because I didn’t do as I was told. I just wanted a friend.”

But Badenoch said thorough police investigations failed to identify Scott, nor was there any evidence of a murder.

Beech claimed Lord Brittan was a “mini-Harvey” who enjoyed putting his head under water and claimed Proctor tied a boy to a table and murdered him in front of him, the court heard.

Badenoch said: “Carl Beech [claimed he] had held the boy’s hand and begged him to wake up, but he didn’t. Harvey and the other men just laughed. They also said to him that he was next.”

The court heard how Beech carried black journals to his police interviews on to which he made notes and sketches. He provided drawings of the locations of the abuse which he falsely claimed to have made from memory, the court was told.

Among about 20 sketches were scenes apparently depicting child abuse and torture, some of which it was suggested to the jury showed demons as perpetrators. One of the sketches included notes about abuse apparently taking place in and around a swimming pool.

The court was told this form of abuse led to Beech to claim to investigating officers that he had a “lifelong fear of the water and swimming”. However, Badenoch said “quite the opposite is true”, adding: “There are photographs and videos of him doing precisely that all over the world, ranging from swimming theme parks with children to honeymoon snorkelling at depth for shells, and at a pool finally with flippers, mask and snorkel. He even had a waterproof camera for photography.”

The trial, which is expected to last up to three months, continues.