The top detective who was the first officer to dismiss sex abuse allegations against Leon Brittan claims he has been 'hounded out' of Scotland Yard after speaking the truth about the case.

Paul Settle has taken early retirement from the Met after concluding he had no future in the force following his decision to expose the 'incompetence' of colleagues, who carried out a protracted inquiry into the discredited allegations against Lord Brittan.

As he stepped down as a detective chief inspector, Mr Settle blamed Labour deputy leader Tom Watson's controversial intervention in the Brittan rape case for the demise of his 25 year police career.

Ex-Scotland Yard detective Paul Settle (pictured) has taken early retirement after concluding he had no future in the force following his decision to expose the 'incompetence' of colleagues

He also launched a wider attack on Mr Watson over his role in the VIP sex and paedophile scandal.

Mr Settle said he was in 'no doubt' that a 2012 speech by Mr Watson in the House of Commons, which alleged the existence of a powerful paedophile ring with links to a former Prime Minister's advisor, was 'calculated' to damage the Conservative Party.

He also accused the deputy leader and several Labour activists of being 'politically motivated' when they made allegations of sex abuse against a number of Tory grandees that were found to be unsubstantiated.

Mr Settle believes that a former Labour councillor who made a number of unsubstantiated VIP child sex claims was driven by an 'extreme hatred' of the Conservative Party and that another Labour Party supporter, whose accusations of rape against Lord Brittan of rape were dismissed by police also openly loathed Tories.

A retired trade unionist, who had dealings with Mr Watson and who spread untruths about Tory grandees, was described as being a 'well-meaning fantasist' by Mr Settle.

As a result of the Labour smears, the lives and reputations of several respected Conservatives were 'destroyed', he said.

But he reserved his most scathing comments for Mr Watson, who in 2014 intervened in a rape case concerning allegations made by a Labour Party supporter known as Jane, who alleged she was assaulted by former Tory Home Secretary Lord Brittan at his London flat in 1967.

Mr Settle blamed Labour deputy leader Tom Watson (pictured) and his controversial intervention in the Brittan rape case for the demise of his 25 year police career

After an extensive investigation, Mr Settle – who was appointed head of the Met's VIP sex abuse inquiry Operation Fairbank in 2012 - concluded there was no evidence to support the woman's allegations and that the investigation should be closed.

But in May 2014, three months after meeting her to explain his decision, Mr Settle was suddenly removed from his post.

Police carried out a protracted inquiry into the discredited allegations against Lord Brittan (pictured)

He was 'disgusted' to learn that a month earlier, Mr Watson had written directly to the Director of Public Prosecutions, Alison Saunders, asking her to review the decision and demanding that Lord Brittan – who was dying of cancer - be interviewed. The letter was forwarded to Met chiefs.

Mr Settle said: 'The management at the Yard were absolutely petrified of Tom Watson. They were scared of what he could do to their careers.

'They hung me out to dry. It was about their self-preservation. I was an expendable DCI and their careers were more important to them.

'I was quite emphatic that the allegations against Lord Brittan were nonsense.'

So outraged was he by what he saw as political interference and the 'unlawful' interviewing of Lord Brittan under caution by the Met, that Mr Settle was the only senior detective to warn of a 'baseless witch-hunt' when he appeared in front of the House of Commons Home Affairs Select Committee in October 2015.

A year ago he was finally vindicated when a damning report by retired High Court judge Sir Richard Henriques into the Met's handling of the disastrous investigation exonerated Mr Settle of any wrongdoing.

He has also been cleared of three 'false' misconduct allegations made against him by members of the public

In his first interview since he retired from the Met last month (November), Mr Settle added: 'Watson was briefed fully on the Jane case by me and was asked to contact me directly if he had any concerns.

Ex-Tory MP Harvey Proctor is seeking up to £1million in damages from the Met over their handling of his case

'But he chose to write an inflammatory letter to the Director of Public Prosecutions.

'He has been in public life long enough to know what the impact of that would be.

'I was incredibly disappointed by how nobody at the Met spoke to me and instead just sided with Watson.'

As a consequence of Mr Watson's intervention, said Mr Settle, he was 'completely sidelined' by senior colleagues and given a non-job marking exam papers.

More than 30 allegations against former prime minister Sir Edward Heath (pictured) were dismissed by Wiltshire Police

He had a mental health breakdown and was on a combination of sick and gardening leave for three and a half years before leaving the force and the job he loved last month.

Mr Settle, 44, said that it was after he was sidelined from running the VIP child sex abuse inquiry, Operation Fairbank, that the sensational 'Nick' allegations about a murderous Westminster paedophile ring surfaced.

'I made the observation very quickly that Nick was either the most unlucky man on the planet or he was a complete and utter fantasist.

'One of my officers interviewed Nick to start off with.

'I told my colleagues about my concerns about Nick, I told the officers concerned, what my views were. But at that point but Met was very excited about getting some high-profile scalps and proving murder.

'I would suggest they got carried away with that, rather than objectively looking at the truth and examining the facts.'

The CPS is currently considering whether to prosecute Nick for perverting the course of justice and fraud in relation to his bogus claims of VIP abuse and murder.

Should he be prosecuted? Mr Settle said: 'If the evidence is there, he should be charged. He has done more harm to victim rights' than anyone in modern criminal history.'

Mr Settle – who was appointed head of the Met's VIP sex abuse inquiry Operation Fairbank in 2012 - concluded there was no evidence to support a woman called Jane's allegations that she was raped by Lord Brittan (pictured with his wife Lady Diana Brittan)

His comments about the running of the VIP sex and child abuse investigation will be keenly read by lawyers representing ex Tory MP Harvey Proctor, who is seeking up to £1million in damages from the Met over their handling of his case.

Mr Proctor was falsely accused of serial child sex murder and rape by Nick, whose far-fetched allegations were taken seriously by the Met and resulted in his (Proctor's) home being raided at dawn and him being interviewed under caution.

Former defence chief Lord Bramall (pictured) was falsely accused of abuse by Nick

Former defence chief Lord Bramall, falsely accused of abuse by Nick, and the widow of Lord Brittan, whose husband was wrongly accused by both Nick and Jane, have each received about £100,000 in compensation from the Met.

Mr Settle says he has no regrets about speaking out about the VIP sex and child abuse scandal – even though it took a huge toll on his mental health. He has suffered severe depression and PTSD, and is retiring early on ill health grounds.

'People forget that you join the police to help people. To have that taken away from you is quite debilitating,' he said.

'I was hounded out at the Met purely because I stood up and said 'we should not do that'. But I can look myself in the mirror. I did the right thing.

'However it was patently obvious that having exposed the failings of senior officers - and the level of indecision that existed and some would say incompetence - that I had no place in the organisation.'

'I have been vindicated in the end but I have lost the job I love.'

Scotland Yard said last night: 'Paul Settle retired from the Met in November. As an employer we consider the grounds on which an individual retires to be a private matter between us and the employee.

'The Met misconduct investigation resulted in no case to answer. The Met does not believe that Mr Settle was "hounded out" of the organisation.'

Mr Watson declined to comment.