A British businessman who is fighting an “unbearable” 20-year extension to his jail term in Dubai said he was banned from speaking about his living conditions during a High Court trial on Tuesday.

Appearing by video link from Al Awir prison, Charles Ridley said he was being watched by a policeman as he gave evidence to judge Lionel Persey QC.

It was the first time the 62-year-old had gained access to a computer during his 14-year detainment, despite his involvement in several complex legal battles surrounding the bank fraud he was originally jailed for. 

Ridley, who had a beard and wore a white tunic, appeared to defer to the policeman for permission to speak at certain points during his testimony.

He warned: “If I could just say, one of the conditions of the prison allowing me to appear in these proceedings is that I am not permitted to talk about the prison conditions.”

His legal team previously described his situation as “harsh and unforgiving” and in a witness statement Ridley said he fears he may die there. 

The former private banker added: “To be held here seemingly for ever is unbearable.”

It comes after a cross-party group of peers and MPs said the case against Ridley and his former business partner Ryan Cornelius amounted to “state sanctioned persecution”.

The two British expats have been held in the emirate since 2008. They were convicted in 2011 for their part in a scheme to defraud Dubai Islamic Bank over a $501m loan.

But although they completed their original 10-year sentences, DIB petitioned for them to be incarcerated for another 20 years under the local Law 37. 

Ridley argues this move violated an earlier settlement agreement in which the bank agreed to take no further action against them. 

The bank rejects this and claims it is doing its legal duty. It says Ridley and his former associates still owe hundreds of millions of dollars.

However, Ridley insists he has no way of repaying the “impossibly large” sums.

“It is risible to suggest that I would have suffered 13 years of imprisonment and face the imposition of a further 20 in order to protect a secret stash of money; even more so, when my wife has been destitute for the last many years as a result of my imprisonment,” his witness statement said. 

He said he first learned of the extension to his prison term in May 2018 when he was woken without warning at 6am, handcuffed and bussed to a “small, dingy office” above a Dubai courthouse where none of his interlocutors spoke good English. 

Meanwhile, he claims DIB “deliberately and maliciously” instructed prison officials to deny him his legal right to access the outside world, thereby blocking him from raising any funds. 

“The bank wants to keep me in prison and have the key thrown away,” his statement added.

“It is a manifest injustice in those circumstances for the bank to invoke Law 37 to keep me in prison for – in all probability – the rest of my days.”

The trial continues.