Mr John Adoboli, father of the arrested rogue dealer Kweku Adoboli has told the Daily Telegraph that his son had made “a mistake or wrongful judgment”.

The retired United Nations employee, said from his home in Tema, Ghana, that “we are all here reading all the materials and all the things being said about him. The family is heartbroken because this is not our way of life.

“I brought them up to be God-fearing and to appreciate decency. Growing up and through to school days they were very brilliant and respectful. ”

Mr Adoboli was educated at the £19,635-per-year Ackworth boarding school near Pontefract, West Yorks, and is described as a “computer whiz” by friends. Neighbours said he had been working long hours recently, often at night, and rarely seemed to be at his east London home.

Before he was arrested, he had changed his status on his Facebook page to “I need a miracle”.

Mr Adoboli, who was arrested at his desk on Thursday September 15, is alleged to have lost £1. 3 billion through his rogue trades.

The scandal wiped £4 billion off the value of shares in UBS, affecting thousands of pensioners whose funds had invested in the company.

The BBC is reporting this morning that UBS only became aware of the unauthorised trading when Mr Adoboli told them, and that the bank's monitoring systems had not picked up the loss.

The loss uncovered by UBS is almost exactly the same amount the bank was trying to save by cutting 3,500 jobs from its worldwide empire. The bank insisted none of its clients had lost money as a result of the trades, but City analysts said UBS could suffer “significant reputational damage”.

Mr Adoboli, who until recently lived in a £1,000-a-week loft apartment in the City, is described by friends as “a really relaxed, happy guy”.

Recently, however, he had spoken to friends about the pressures of working in the City following the financial downturn, describing it as a “fight”.

Mr Adoboli’s arrest came on the third anniversary of the collapse of Lehman Brothers, seen as the pivotal moment in the worldwide banking crisis.

UBS was one of the banks which had to be bailed out at the height of the banking crisis, accepting help from the Swiss government because of its “toxic” assets in 2008.

In the same year it was accused by the FBI of helping clients to evade tax, and agreed to pay a fine of $780 million (£493  million). UBS employs 6,000 people in the UK and 65,000 worldwide.

Its staff was told about the alleged fraud in a round-robin email yesterday morning.