A cagefighter has admitted helping to plan Britain's biggest cash robbery.

Martial arts enthusiast Paul Allen, 31, plotted the heist with fellow fighter Lee Murray, 30, at the Securitas cash depository in Tonbridge, which netted the robbers £53 million.

The depot manager and his family were kidnapped and taken hostage while 14 staff were held at gunpoint during the raid on the night of February 21-22 2006.

Within days of the robbery the fighters had fled to Africa via Amsterdam to begin a new life.

Allen, a rival to Jordan's cagefighter boyfriend Alex Reid, was extradited back to the UK to face trial but Murray remains in a Moroccan jail.

Allen, of Huntersfield Close, Chatham, admitted three charges relating to the robbery during a secret hearing at high-security Woolwich Crown Court on Monday. He faces sentence on Monday October 5.

He was facing a retrial after a jury failed to reach verdicts after a trial at the Old Bailey that ended in January.

Allen, known as The Enforcer, was the best friend and right-hand man to Murray, who successfully fought against extradition back to this country.

Allen pleaded guilty to three counts of conspiracy to kidnap, conspiracy to commit robbery and conspiracy to possess a firearm.

But he made the admissions on the basis he did not enter the depot as one of the robbers, nor was he one of the kidnappers and he did not handle or obtain any firearms.

He admitted he was an employee of Lee Murray before, during and after the conspiracy but said he was not one of his partners.

Allen also said his benefit from the conspiracies was limited to property obtained in Morocco.

In February last year five men were convicted and two acquitted of taking part in the robbery.

Roger Coe-Salazar, chief crown prosecutor for Kent, said: "The Securitas robbery was meticulously organised and we have never had any doubts that Paul Allen played a pivotal role in the planning and execution of it."

Afterwards, Kent Police's Chief Constable Michael Fuller said: 'Today's guilty plea means an end to this part of the proceedings in this country. It does not mean an end to the investigation and by no means an end to recovering the outstanding money or assets obtained through the proceeds of this robbery.

"The victims of this crime still live with the memories of what the robbers put them through. I'm pleased that by entering a guilty plea, they do not have to recount their horrific ordeal once again.

"It is also testimony to the hard work of my officers for the thousands of hours put into the investigation of this crime and our work with the Crown Prosecution Service to bring the offenders to justice.'

Mr Fuller continued: "The enquiry in respect of Paul Allen was made more complex by the need to extradite him from Morocco. He was arrested on June 26 2006 in Rabat in respect of domestic offences. These criminal proceedings had to be concluded before extradition could take place.'