Ordeal: Harvey Proctor (pictured) went through hell because police believed fantasist Carl Beech

Last Saturday, Harvey Proctor attended a party at Belvoir Castle, hosted by his friend, the Duke of Rutland.

As pre-dinner drinks were served, several of those gathered in the dining room at one of Britain's finest stately homes raised their glasses to congratulate the former Conservative MP.

Two days earlier, after a difficult and lengthy legal battle with Scotland Yard, Mr Proctor, 72, received £500,000 damages (and £400,000 legal costs) for a life ruined in what we now know to be one of the most staggeringly inept, if not downright negligent, child sex abuse inquiries of our time: Operation Midland.

Yet Harvey did not — does not — feel jubilant. 'When the Duke invited me and Terry [his partner of 40-odd years] to go, I said: 'You'll forgive me if I feel I'm not up to it nearer the time?' I didn't know what would happen on settlement day or how I'd feel afterwards,' Harvey explains in his first in-depth interview about his four-and-a-half-year ordeal.

'I don't feel in a celebratory mood — not at all. The police officers responsible for all of this have been promoted, enriched or ennobled and are leading a better life. For what? Abject failure. That's not right.

'I don't think I can ever be happy again. I mean it. I can't visualise a day until I die when I won't be thinking about this. It's not something that's going to go away. I can't ever accept what happened.'

Harvey Proctor has made a statement of complaint of criminality against five of the officers involved, and now reveals he has also sent a statement to the Met insisting that Commissioner Dame Cressida Dick (pictured) be investigated for misconduct

That is understandable. He lost his job, his home and almost his sanity when the Metropolitan Police took the word of a complete fantasist known as 'Nick' and threw him to the wolves without a single piece of evidence. Earlier this year, the delusional liar we now know as convicted paedophile Carl Beech was found guilty of 12 counts of perverting the course of justice and one of fraud.

The appalling allegations of rape, torture and murder he made against, among others, former Prime Minister Edward Heath, former Home Secretary Lord Brittan and the former head of the Armed Forces Lord Bramall, as well as Harvey, would have been laughable if they hadn't been so devastating to those accused.

Yet, astonishingly, right from the start, the Metropolitan Police deemed the preposterous allegations 'credible and true'.

Harvey Proctor has made a statement of complaint of criminality against five of the officers involved, and now reveals he has also sent a statement to the Met insisting that Commissioner Dame Cressida Dick be investigated for misconduct.

For, as she has since acknowledged, she knew that 'credible and true' remark, made at a Press conference by a senior officer in 2014, was 'a mistake', 'an error', 'wrong' and should have been withdrawn.

'I was so incensed when I heard her say she knew that statement was a mistake, but did nothing about it,' says Harvey. 'If somebody had written a novel and put in it these claims of a VIP Westminster paedophile ring, no publisher would publish it, because it would be regarded as too far-fetched.' He shakes his head.

His jaw works back and forth as he tries to control the tears that threaten throughout our interview. It is one of several techniques that a therapist has given him to help keep his emotions in check.

Earlier this year, the delusional liar we now know as convicted paedophile Carl Beech (pictured) was found guilty of 12 counts of perverting the course of justice and one of fraud

He is, he says, 'not the same man I was before'. His shoulders are stooped and his mental health has suffered. Terry tells him he is more argumentative than he used to be. Harvey recognises he is 'not as patient', 'more strident', 'changed'.

'I have had a couple of [counselling] sessions because I have some issues,' he explains.

'Before this, I could control my emotions. Stiff upper lip, you know. I'm a Yorkshireman, and I don't want to be doing this [being so emotional], but I can't stop and . . . I can, for no reason, suddenly get very depressed. Everything is lost.

'None of this is right. Can you believe social services insisted to the Duchess of Rutland that they interview her children to see whether I'd done anything with their sons?'

The reason for mentioning the Duchess is that Harvey and Terry were living on the Belvoir Castle estate at the time of his arrest.

Harvey had worked as the Duke's private secretary since 2002, and regards their five children much like family. He has known their eldest son, Charles, Marquess of Granby, since he was three and 16-year-old Lord Hugo Manners all his life.

By 2015, Harvey was a highly trusted member of the team. The castle is one of the finest examples of Regency architecture in the world and he was negotiating filming contracts for productions including The Young Victoria and The Crown.

He organised guided tours and corporate events, hosted more than 360 weddings and was, in short, the Duke's right-hand man.

Six years ago, he, Terry and their two dogs moved into a renovated farmhouse on the estate with 'wonderful views across the farmland to the castle and fantastic skies looking west'.

'We had a hand in the renovations because it was going to be the house in which Terry and I died,' he says. 'I was completely content, with a reputation I'd worked hard to obtain.

'I had an interesting, varied job, which didn't feel like work, met an incredible variety of people and knew I was well thought of.' But then, at 8am on March 4, 2015, no fewer than 18 police officers in blue forensic uniforms arrived with a search warrant.

'Terry and I were in bed listening to [BBC Radio 4's] Today programme,' he recalls. 'We had a glass door and Terry said: 'Oh, there's a police van there.'

'I thought something had happened at the castle. I put my dressing gown on and went to the door.

'The first thing they said was: 'Can you get your dogs under control?' They were barking. I said: 'Forgive me, this is their house. You have to just be patient.' After I'd got the dogs into the garden, the police came in and showed me search warrants for potential offences of historic child sexual abuse.'

Officers turned his home upside down for 15 hours.

'You feel defiled and fearful because you genuinely don't know what they are going on about,' he says. 'At some stage, I said: 'I've only seen something like this on television.'

'I was in a shocked state, trying to get titbits of information from the police, trying to identify what it was I was supposed to have done. But, of course, they were very careful not to say anything. The only thing I could think of was that it was something to do with 1987.'

This was the year Harvey had been forced to plead guilty to four charges of gross indecency, then step down from politics after a tabloid sting exposed him for having consensual sex with a man under the age of 21 in the privacy of his own home.

Harvey maintains he 'genuinely did not realise [the man he met when he was separated for several years from his partner] was under 21'.

In any case, the 'crime' was later abolished as a sexual offence when the age of consent for homosexuals was lowered to 16.

Yet he was vilified afterwards — spat at in the street and later violently assaulted — and even contemplated suicide. Of that time, he says: 'All my life, I'd wanted to be an MP [he was elected in Basildon in 1979]. I didn't think there was anything left afterwards.' He says it took him 28 years to rebuild his life.

'I was terrified knowing what the reaction had been before — being abused and shouted at on the streets. Now, they were talking about how the homicide squad and child abuse squad were investigating allegations, whatever they were. I thought: 'If this gets into the papers, it's going to be far worse for me.'

'So I said: 'Can I have your assurance there'll be no mention of my name?' They said: 'Yes.' '

That night, Harvey, exhausted and emotionally overwrought, fell asleep without turning off the TV. 'In the morning, Terry and I woke up at 7am to see my face on the screen.' Harvey's voice breaks. He has since discovered that an officer phoned Beech within an hour of entering his home to tell him about the raid. Media outlets, including the BBC, were tipped off.

Harvey, never arrested in relation to Beech's fantastical claims, was nevertheless being hung out to dry.

Worse, he later discovered, Leicestershire police and social services, at the behest of Scotland Yard, were holding 'secret, private' talks with the custodians of Belvoir Castle.

'They went to see the Duke and said: 'Did you know about what happened in 1987?' He said: 'Yes, of course. The world knows about that. It was in every newspaper.'

'Representatives of the Duke and Duchess were told I shouldn't be working at the castle or have any connection with children as part of a safeguarding operation.

'Once they'd searched my house, they were able to say openly they were looking at allegations of murder and child abuse. Social services told the representatives that if they couldn't make sure I wasn't involved with children — and how could they? The Duke and Duchess have five children, and children come to the weddings and other events — then they'd write to our clients.'

Two weeks after the search, a lawyer from the estate visited Harvey at his home. 'She said: 'I'm very sorry. Either you have to resign or we will have to sack you.'

Everything was lost. It was the 1987 moment over again, only writ large because the allegations were so much graver. 'The Duchess did come round to talk about it and to say she was sorry this was happening. Clearly, she didn't want to sack me, but for the protection of the business and the protection of her children, she didn't have a choice. I understand that.

'The Duke and Duchess have been friends to me throughout this. But, largely, people fall into three categories: those like Terry and others who believed in me throughout, completely and utterly; those who dropped me like a stone and still have; and those who dropped me until I was cleared, then tried to get back into good relationships.

'I'm not sure which is worst of the last two categories.'

Harvey had no choice but to resign, in the process losing the house that came with his job. He and Terry went to live in Spain for a while, returning in June 2015 for his first police interview.

'Three days before, my solicitors asked me to go to see them to go through the disclosure document,' he recalls. 'The reason they didn't email it is because the allegations were so horrific they wanted to be with me when I read them. They didn't want me to be alone. Terry was there, too.

'Strangely, I felt a combination of things. Firstly, absolute horror at what I was supposed to have done and that anyone could think I could conceivably have done any of that.

'Secondly, incomprehension that the police could have said 'credible and true' to all of that.

'Thirdly, relief, in the sense that I now knew what I had to face and that absolutely none of it had happened. Now, it was just a question of proving it.'

Harvey decided to fight fire with fire. After a second police interview, he held a Press conference on August 24, 2015, and read the list of monstrous allegations summarised by the police. 'I decided to appeal to the media to investigate these heinous claims and help clear my name. I'm indebted to most of the media, particularly the Daily Mail, for believing in me, adopting my case and investigating it.'

He highlights my Mail colleague Stephen Wright for his 'forensic' research and dogged determination to hold Metropolitan Police officers to account.

Still, Harvey would have to live under the threat of truly heinous allegations until police, on March 21, 2016, issued the 'weaselly worded' statement that 'no further action' would be taken — hardly a ringing endorsement of innocence.

'It wasn't until February this year, when a senior police officer gave evidence to the Independent Inquiry into Child Sexual Abuse, that they said the Metropolitan Police believed there was no Westminster VIP paedophile ring,' says Harvey.

'When I saw Carl Beech in court [during Beech's trial earlier this year], my feeling towards him was icy contempt. It is the Metropolitan Police who did the damage.

'Cressida Dick has tried to say they were Beech's lies, not the Metropolitan Police's lies — that he was a very good liar and we're sorry we believed him. No. He was a very bad liar. The lies were obvious and easily disproved.

'Lies about murders, about torture with snakes and wasps. The lies were utterly nonsensical — cuckoo — but they said they were 'credible and true'.'

After the police search, he contemplated suicide. 'The only reason I decided not to do it was that people would then say: 'Ah, told you so. He's killed himself because he's done something.'

'For 18 months, I had to fight for this compensation for all they destroyed. They were insisting I hadn't lost my house and job because of Operation Midland until the Duke confirmed I had.

'I accepted their offer last week because, if I hadn't, we'd have had to go to trial. That would have taken another two to three years. Terry and I need some stability in our lives. It's nowhere near the full financial losses I have suffered, but I also believe the settlement is sufficient for most reasonable, rational people to determine that the Metropolitan Police got this wrong.'

After returning from Spain, for 18 months Harvey and Terry lived in a single-roomed annexe in the garden of a friend. Now, they share a two-bedroom cottage in the estate grounds and are slowly rebuilding their lives.

But, while Harvey may have found some stability once again, he will clearly never forgive and forget.

He adds: 'I made it quite clear when I accepted their settlement that there would be no gagging order. I will keep up my attack on the Metropolitan Police until I take my last breath. I will not rest until at least one police officer is held personally responsible for what happened.

'Victory will be mine only when I am content that the Metropolitan Police can never put other innocent people through what I have experienced these past five years.'