A Collier Row man has been jailed for seven years after he admitted removing court-imposed electronic tags from at least 37 convicted prisoners out on bail or early release.

Martin Crean, aged 49, of Collier Row Lane, had pleaded guilty at Snaresbrook Crown Court on Thursday, January 19 to 34 counts of perverting the course of justice.

He had already pleaded guilty to four additional counts back in August 2018.

Today (Friday, February 7), he was jailed at the same court - seven years for each count, to run concurrently.

The court heard how Crean abused his position while working with Capita Electronic Monitoring Systems (EMS).

Capita EMS has the contract for monitoring, via tagging, prisoners who are on early release and/or court bail.

Authorities had started investigating Crean after an incident on November 16 2016, when police responded to reports of a man assaulted in Plaistow, Newham.

Officers quickly identified one of the suspects, and the next day a warrant was executed at the man's home address.

Investigators were aware the man was on a court ordered curfew and at the time he should have been present at the address, but he was not.

Enquiries with Capita EMS established that, although he was not present, his electronic tag showed him as being at home. The tag also showed no signs of having been tampered with.

Capita EMS immediately launched an internal investigation and it was established that this person's tag had been reset by an EMS fitting tool (serial number 10416) away from his home address.

This meant the tag had been cut from the ankle, had a new strap fitted to it, and then reset to delete any record of the tamper. This gave the tag the electronic appearance of being complete, but it was no longer attached to the person's ankle.

The Metropolitan Police were informed and an investigation, 'Operation Glenn Falls', was launched to establish the facts.

Crean - an ex-Capita employee who had already left the company after an internal investigation into other matters - was soon identified as the person who had reset the tag.

He resigned on Sunday, October 30 2016, prior to a formal disciplinary hearing.

On Tuesday, January 3 2017, a warrant was executed at Crean's home address in Collier Row and he was arrested for conspiracy to pervert the course of justice.

During a search of his home, multiple pieces of EMS equipment were recovered, including the fitting tool 10416.

Crean was interviewed and then bailed pending further enquiries.

As a result of the analysis of the recovered fitting tool, it was found that between 2015 and 2017 there were 37 cases of persons having their tags unlawfully tampered with.

The last offence was committed after Crean's arrest and while he was on bail; he utilised a second tagging machine he had unlawfully obtained from another member of then Capita staff.

As a result of this, in January 2017, police began making arrests of tagged offenders and also arrested a further two people who had been employed by Capita EMS. Of the Capita employees, one was later released without charge and the other was found not guilty at a subsequent trial.

In all 35 people, not including Crean, were charged with conspiring to pervert the course of justice in relation to the investigation.

Six were found not guilty, 11 were convicted after a trial, 17 pleaded guilty and one case was not proceeded with.

A review of the activity of those whose tag had been tampered with suggested that, in the majority of cases, the offenders were engaged in acquisitive crime and drug related offences.

The police have also confirmed that no one was charged with committing any offences of serious harm while using the tampered tags.

During the investigation, officers worked in partnership with Capita EMS to utilise cell site analysis and the raw data stored on systems to compile evidence.

This showed a pattern of offending whereby Crean had been providing his illegal services in exchange for money.

Tagged offenders would contact Crean directly, or through one of the other defendants, and arrange to meet him at locations around London and Essex which were always away from their home addresses.

He also provided them with instructions on what to do in case they were at risk of being detected.

Then, just prior to the end of their curfew period, they would meet Crean again who would re-fix the tag to their ankle so that suspicions would not be aroused when Capita EMS staff came to legitimately recover the equipment.

Crean and 28 other defendants were charged with conspiracy to pervert the course of justice between Monday, 13 November and Wednesday, 22 November 2017.

All 29 appeared at Thames Magistrates' Court on two dates - either Wednesday, 20 December or Friday, 22 December 2017.

As the investigation continued, there were further charges against other individuals.

Reporting restrictions were imposed to avoid contempt of court as the numerous trials were completed.

Of those charged only one case was not proceeded with, this related a man who received a long custodial sentence for a matter that was unrelated to and not affected by this investigation.

However, all the other defendants received terms of imprisonment, with the length of the sentences ranging from 9 to 36 months in prison.

The total term of imprisonment imposed on all those convicted amounted to more than 42 years.

Det Con Robin Kyle, from Specialist Crime, said: "Crean abused his position of trust and undermined an important part of the judicial system. Men whose activities should have been closely controlled, by order of the courts, were free of any restraint and indeed provided with the perfect alibi.

"Thankfully we can find no evidence that those whose tag was tampered with caused serious physical harm to anyone, but that was only by good fortune. Crean was motivated only by greed and he cared not one wit that he was placing the public at risk.

"I hope the sentencing of Crean, our relentless pursuit of all those who conspired with him and the combined sentences of over 42 years, reassures the public that those who seek to undermine our justice system will be relentlessly pursued and brought to account."