The News of the World hired private detectives to spy on a former Metropolitan police commissioner, Independent Voices can reveal.

Lord Stevens, who led Scotland Yard between 2000 and 2005, was placed under surveillance by Southern Investigations, a firm of private investigators linked to one of London’s most notorious unsolved murders.

Its co-founder Jonathan Rees claims the defunct Sunday tabloid hired his company to watch Britain’s most powerful policeman in 1999. He said Southern Investigations received a tip that the then-deputy commissioner was using taxpayer funds to fly a Metropolitan police plane up to Northumbria to see a mistress. There is absolutely no suggestion the tip off had any foundation.

At the time, it can also be disclosed that Scotland Yard had an undercover officer – Derek Haslam - inside Southern Investigations who warned police that the firm was also trying to obtain other embarrassing information on the former Commissioner.

As well as selling the story to the News of the World, Haslam claims Southern Investigations also wanted to use the sensitive information to “control” Lord Stevens.

Haslam said: “I told my handler ‘you’d better tell him they are on to him and they are looking at anything’. They saw filth on police and politicians as a way to control them.”

However, in an interview with Independent Voices, Rees rejects the bombshell allegation as absurd.

Asked if he had Lord Stevens put under surveillance, he replied: “We were given instructions and an allegation that he was using a Met police plane from Biggin Hill to see his mistress in Northumbria.

“Now we did organise a surveillance team because it’s what the News of the World wanted and we had team in Northumbria and here, but he never showed so whether the allegation is true or not, who knows.

“The allegation was that he was using…a Metropolitan police federation plane bought by donations from charity, and the petrol, the fuel, to travel up to Northumbria to see his mistress. You can see why people wanted…that story.”

Haslam’s take on Southern Investigations’ activities is very different. During his nine years as a police “mole”, he claims he told the Yard the firm was committing a vast array of crimes – often on behalf of the News of the World.

Given the widespread criminality he was reporting back to his handlers, Haslam was astonished and confused when no-one was arrested. However, his suspicions were raised last July when the relationship between the Murdoch media empire, Scotland Yard and senior politicians came under intense scrutiny after it emerged that the News of the World hacked the phone of murdered schoolgirl Milly Dowler, 13.

The scandal led to the resignations of David Cameron’s chief spin doctor Andy Coulson, two Scotland Yard police chiefs, ex-Murdoch lieutenant Rebekah Brooks and cost almost 300 jobs when the News of the World was forced to close after 168 years.

Following the recent revelations, Haslam now believes one reason for the Yard’s inaction was “an unhealthy association between senior police officers and News International”.

He refused to speak to Independent Voices because he is currently suing the Met. However, we obtained a confidential briefing he passed to investigators. The 65-year-old claims he told the Met that Southern Investigations was “a corrupt organisation that was corrupting police officers and illegally accessing all sorts of confidential information”.

He added: “I told my handlers that MPs, ministers and Home Secretaries were targets. They fell into two categories, one they could earn money from and the other was to use blackmail, influence, to do their own thing. Anything that put the Met in a bad light, or anybody they could infiltrate or put in a bad light. It was about money and influence.”

Rees described Haslam’s allegations as “nonsense”. He claims Scotland Yard asked Haslam to infiltrate Southern Investigations to invent “blatant lies” and smear them at a time when the firm was uncovering police corruption on behalf of the press.

He said: “Haslam was tasked by senior officers to…come in there and mix with us again and…to find out…what we were doing against CIB3…they knew we were investigating CIB3…it was a force within a force, they were given total autonomy to do whatever they liked, their own accounts, their own finances…history tells us that when you allow policemen to do that it goes wrong….if you let these squads run themselves it leads into trouble.”

Rees claims to have seen the Met’s applications for audio probes inside Southern Investigations’ offices and said the Yard justified the intrusive surveillance because the firm might “undermine the structure and the moral wellbeing of the Metropolitan Police…or even bring it down”.

He added: “We’ve got this poxy little firm of private investigators, half a dozen men, suddenly they are alleging that we were going to bring down the Met police. Good arguments to get your surveillance and come in and listen to what we are saying about them. They were abusing and using the process to see what we’re doing against them. So a battle started….things got very dirty indeed.”

Haslam’s undercover work for the Met began in 1997 when he was asked to infiltrate Southern Investigations to gather evidence on Rees, who was a suspect for the murder of Daniel Morgan, the firm’s co-founder who was found with an axe embedded in his skull in a south London pub car park in 1987.

He claims one of Southern Investigations main clients was former News of the World executive editor Alex Marunchak whose name was “constantly mentioned” inside the firm.

Haslam alleges the veteran journalist paid Southern Investigations to source confidential information from corrupt serving officers on celebrities and high-profile police chiefs, that reportedly included Tony Blair, Kate Middleton, Alastair Campbell, Jack Straw, Lord Mandelson, Lord Stevens, and John Yates – a claim both Southern Investigations and Marunchak strongly deny. When asked about these allegations Mr Marunchak stated that he has never commissioned Southern Investigations to obtain any confidential information relating to celebrities, politicians, the Royal Family, police investigations, any third party or to commit any illegal acts.

Working under the codename “Joe Poulton”, Haslam alleges he also told his handlers at the Met that Southern Investigations tried to obtain the new identities of people inside Scotland Yard’s witness protection programme.

In one of his confidential reports to the Yard in 2006, seen by Indy Voices, Haslam warned the Met that Rees was paying visits to Epsom police station in Surrey “in an attempt to ingratiate himself with serving officers…to the detriment of the service”. He added Rees described the trips as a “loss leader” as he could make money from his efforts.

In another section of the report, Haslam told the Met: “(Rees) still asks about accessing police sources for saleable information.”

Perhaps the most shocking allegations from Haslam was that Southern Investigations burgled MPs’ homes and photocopied documents in a bid to obtain embarrassing titbits they could sell to the News of the World.

Rees totally denies he was ever involved in anything illegal. He said: “The allegations in that report are not true…They know it’s not true and the people who were instructing him didn’t care. I think he was directed to make the worst report, the worst allegations he could…”

“He alleges that…(Southern Investigations) burgled an MP’s garage to remove a briefcase, photographed the contents of the briefcase and put that back…that is a lie.”

Later, he added: “We’ve got nine years of (Haslam) claiming we were involved in criminality. If there was one iota of evidence in there, CIB3 would have liked nothing better than to kick our door in and arrest us. They never did that, because there was no evidence there. It’s in Haslam’s fabricated reports …it’s smoke and mirrors at its best…they will continue to do that to justify all the wrongdoings and corrupt gathering of evidence.”

Haslam started his undercover work around the same time the Met launched a separate third investigation into the Morgan case, which the Yard publicly admits has been plagued by police corruption and remains unsolved 25 years later.

Codenamed Operation Nigeria, the seven-month probe – which was separate to Haslam’s work - was led by former Detective Superintentendent Bob Quick, who later rose to Assistant Commissioner rank in charge of Britain’s fight against terrorism. The covert operation included bugs installed inside Southern Investigations’ offices in Thornton Heath to record any discussion of the Morgan murder. During the inquiry, Quick said Scotland Yard became aware of the firm’s close links to News International.

He told the Leveson Inquiry he recommended establishing an investigation into the relationship between journalists, private investigators and police officers in 2000. However, Quick claimed the Met never took up his proposal. In his witness statement to the Leveson Inquiry, he said Southern Investigations, acting on behalf of various News International journalists, obtained confidential information from serving police officers in order to sell stories to newspapers. “One of the journalists suspected was Alex Marunchak, an executive with the News of the World,” he said. “During the operation it became clear that officers were being paid sums of between £500 and £2000 for stories about celebrities, politicians, and the Royal Family, as well as police investigations.” Mr Marunchak was the News of the World’s chief crime reporter before being promoted to the roles of executive editor and, finally, the paper’s Irish editor.

This allegation is supported by a witness statement provided to police by Southern Investigations’ book keeper Marjorie Williams, who claimed the News of the World used to invoice Southern Investigations up to 500 times a month via Marunchak.

She also alleged the firm paid £7,000 off his credit card and used to fund his child’s school fees. Marunchak strongly denies any claim that Southern Investigations paid his debts. He stated that it is categorically untrue that Southern Investigations has ever paid monies into his credit card accounts or towards his children’s school fees. He also stated that he has a “signed, witnessed, dated statement of truth” from the then bursar of his children’s’ school that confirms no-one except Marunchak ever paid fees .

Rees backs Marunchak’s version of events. He said: “It is a serious allegation…why she says those things, I suspect there’s some ill-feeling there…the police, right from the early days, have had our accounts…and there is not one slip or iota of evidence to show any of that is true.

“We never paid Alex Marunchak any monies… he never, ever asked us to pay his childrens’ school fees.”

During Operation Abelard – the Met probe into the Morgan murder that followed Nigeria in 2002 - detectives managed to persuade another former employee of Southern Investigations, Richard “Boris” Zdrojewski, to give evidence against Rees. In his witness statement to police, seen by Indy Voices, he said one “particularly memorable job” was when the firm “fitted up” a police officer for a News of the World story. He stated that he arranged to meet a chief inspector in a McDonalds car park with some information on a bogus crime.

Mr Zdrojewski added: “I shoved (the papers) into his hands. He was photographed and his photo and report appeared in the News of the World to look like he was taking a bribe.”

Rees said this is yet another allegation invented by police to discredit him. He added: “It is a ridiculous allegation…it’s nonsense. The truth is that we were serving an injunction on a senior police officer who happened to be the head of the domestic violcene unit…we were serving an injunction from his wife because of domestic violence on her…that was a story.”

Independent Voices can reveal that Lord Stevens had lunch with Rebekah Brooks, then editor of the News of the World, Alex Marunchak and Dick Fedorcio, the Yard’s former press chief, in 2000 – just months after the conclusion of Operation Nigeria.

Further links between Scotland Yard and News International emerged during Abelard, which commenced in June 2002. The senior investigating officer, detective chief superintendent Dave Cook, discovered that News International had apparently agreed to use photographers and vans leased to the News of the World to run surveillance on him and his family.

The defunct tabloid allegedly collected a huge amount of personal information on Cook and his wife Jacqui Hames following the policeman’s appearance on BBC Crimewatch, when he appealed for information to solve the Morgan murder.

But when the Met discovered what was happening, the only action it took was to summon the then News of the World editor Rebekah Brooks into a meeting in January 2003 where she was told about the surveillance of Cook and about Marunchak’s relationship with Rees. Brooks said the newspaper suspected the couple of “having an affair with each other” - despite Hames and Cook being married for four years with two children, and a profile of them appearing in Hello! Magazine. Marunchak denied any involvement in any attempt to target the couple and stated that he never commissioned Southern Investigations to obtain confidential information relating to Hames and Cook . He said his sole link was to receive a tip that Hames, who presented Crimewatch, was having an affair with a senior officer who appeared on the BBC show and passed it on to the News of the World newsdesk.

Ms Hames told the Leveson Inquiry that Brooks' excuse was “utterly nonsensical”. She said: “I believe the real reason they placed us under surveillance was that suspects in the Daniel Morgan murder inquiry were using their association with a powerful and well-resourced newspaper to try and intimidate us and so attempt to subvert the investigation.”

Rees said: “That anyone would try to intimidate a very senior high-ranking officer in charge of one of the most notorious investigations for the Met police…it’s as if common sense has gone completely out the window.”

During all this time, Haslam worked undercover at Southern Investigations until his cover was eventually blown in 2006 when his computer was allegedly hacked by his colleagues, who had become suspicious. Haslam said Scotland Yard offered him the chance to go into the witness protection programme – a system he claims he saw repeatedly compromised by the agency.

Rees said this was “wholly untrue”. It is understood Haslam turned down the offer of protection, decided he would look after himself and asked for a payout. However, this is thought to have been rejected by the Met.

The fifth and final investigation into the Daniel Morgan murder collapsed last year after Scotland Yard failed to disclose vital evidence to the defence and Rees was released from jail after spending 23 months on remand. In all, the probes have cost more than £30 million.

Detectives working on the various criminal probes into News International have arrested around 80 different people so far. Rees and Marunchak, who supplemented his News of the World income by working as a Ukrainian translator for the Met for 20 years, are not among them.

A spokesman for Lord Stevens denied flying a Met police plane to Northumbria and denied ever having a mistress. He added the ex-Commissioner was unaware he was under surveillance.

News International declined to comment. However, a source emphasised the company was now co-operating vigorously with the Met.