A fourth member of the so-called Stockwell Six, a group of young black men who were “fitted up” by a corrupt police officer nearly 50 years ago, has been found and is mounting an appeal against his conviction.

The Criminal Cases Review Commission (CCRC) announced on Monday that Texo Johnson got in touch after his sister saw the news that three of his friends had had their names cleared earlier this month.

The convictions of Courtney Harriot, Paul Green and Cleveland Davidson were overturned by the Court of Appeal as they were based on the word of corrupt British Transport Police (BTP) officer Detective Sergeant Derek Ridgewell.

The trio, Mr Johnson and two others – Ronald De’Souza and Everett Mullins, who was acquitted – were arrested on the London Underground on a night out on February 18 1972.

The Stockwell Six, as they became known, were accused of trying to rob Ridgewell, who was in plain clothes and had previously served in the police in South Rhodesia, now Zimbabwean.

Ridgewell claimed the six, who got on the train at Stockwell station in south London, attempted to rob him before he fought back and arrested them with a team of undercover officers.

They all pleaded not guilty, but all bar one were convicted and sent to jail or borstal, despite telling jurors that police officers had lied and subjected them to violence and threats.

Mr Mullins was acquitted because it was shown that his reading was not good enough for him to have read and fully understood his signed statement, which was written for him by Ridgewell.

But Mr Harriot was sentenced to three years in prison, Mr Davidson was sentenced to six months’ detention and Mr Green was sent to borstal.

Mr Johnson has now submitted an application to the CCRC, which investigates miscarriages of justice, and is expected to become the ninth person convicted in the 1970s on the word of Ridgewell to finally have their name cleared.

I’m still taking it all in and it’s quite overwhelming – but I’m pleased to have the same opportunity to finally clear my name

In a statement, he said: “It happened such a long time ago so, to be honest, I’d put it to the back of my mind.

“I’m still taking it all in and it’s quite overwhelming – but I’m pleased to have the same opportunity to finally clear my name.”

CCRC chairwoman Helen Pitcher said: “We’d tried a number of ways in the past to try and find Mr Johnson, which is why we were delighted when his sister called and put us in touch with him. It was a good day for us all.”

After his conviction was overturned earlier in July, Mr Davidson described Ridgewell as a “corrupt and wicked and evil police officer” and said his own conviction had affected him for the last five decades and “ruined” his life.

He asked: “We got justice today, but it has not put it right – how can it put it right?”

Ridgewell was involved in a number of high-profile and controversial cases in the early 1970s, culminating in the 1973 acquittals of the so-called Tottenham Court Road Two – two young Jesuits studying at Oxford University.

He was then moved into a department investigating mailbag theft, where he joined up with two criminals with whom he split the profits of stolen mailbags.

He was eventually caught and jailed for seven years, and died of a heart attack in prison in 1982 at the age of 37.

Ridgewell’s corruption has previously led to eight wrongful convictions being overturned by the Court of Appeal.

In January 2018, Stephen Simmons’ 1976 conviction for stealing mailbags was quashed after he discovered Ridgewell was jailed for a similar offence two years after his own conviction.

In December 2019, three members of the Oval Four – who were arrested at Oval Underground station in 1972 and accused by Ridgewell’s “mugging squad” of stealing handbags – also had their convictions overturned.

Winston Trew, Sterling Christie and George Griffiths were all sentenced to two years, later reduced to eight months on appeal, following a five-week trial at the Old Bailey.

In March 2020, the final member of the Oval Four, Constantine “Omar” Boucher, also had his name cleared, prompting calls for a “wholesale review” of all cases linked to Ridgewell.

After Mr Davidson, Mr Green and Mr Harriot’s convictions were overturned, BTP Deputy Chief Constable Adrian Hanstock said the force had “examined all available records” of investigations where Ridgewell was the principal officer.

He said BTP “have not identified any additional matters that we feel should be referred for external review”.