A former colleague of Kweku Adoboli, the City trader jailed for seven years for gambling away £1.5bn of Swiss bank UBS's money, has set up an online betting company.

John Hughes, who was dismissed by UBS after the firm found strong evidence of collusion at local desk level according to evidence at Adoboli's trial, has now co-founded a football betting company called Bets of Mates, in which groups of friends gamble against each other in a league.

Hughes, who appeared as a prosecution witness at Adoboli's trial and told Southwark crown court he "cried all the way home" on the night his colleague was arrested, said he began work creating the website shortly after leaving UBS.

"Obviously, I've been without a job," he said. "I thought it [the website] was a good idea. My best mate is a professional footballer and he's invested in it."

Hughes, who is described as the brains of the operation on the Bets of Mates website, said he could not "pass comment on whether it's appropriate" for a man so closely linked to Britain's biggest ever fraud loss to be running a betting site.

"It's not as though it's the first gambling website," he said. "It's an appropriate use of my skills, hopefully.

"I appreciate there's a story here, but I don't want to be the one to tell it. Obviously the judge has made his comments on that [the role of gambling in Aboboli's fraud]."

Sentencing Adoboli earlier this week, Mr Justice Brian Keith told him there is "a strong streak of the gambler in you. You were arrogant to think the bank's rules for traders did not apply to you."

Hughes told the trial he was aware Aboboli was hiding his unauthorised trades in an "umbrella" account more than six months before the bank discovered the losses, but failed to report it.

The court heard that after Adoboli told him how much money was in the account, Hughes sent a chat message to Adoboli saying: "Nice. It can piss down with rain after this. You're a legend. I don't know how you sleep at night."

He told the court he was "stupid not to have reported Adoboli as soon as he became aware of the unauthorised trades.

Hughes said he had to receive six weeks of counselling iafter Adoboli's arrest in September 2011. "This was a huge trauma," he told the court. "I nearly drove my car into the middle of the motorway. I wasn't a rational human being. I cried all the way home from London to Middlesbrough."

On his profile page on the website, Hughes is described as "a Middlesbrough fan by trade, but seven years in the City removed all sense of optimism from his character, and made him absurdly superstitious".

"Having worked in the City since 2005 John is all numbers and spreadsheets, numbers and spreadsheets, numbers and spreadsheets," it adds.

The website, which uses the slogan "there is always a winner", was set up by Hughes and two friends who had a "drunken idea [to set up the gambling site while] watching the Champions League semi-final in 2012".

Hughes' partners are Adam Haywood, a business development manager, and Dave "TY" McGurk, a centre half for York City.

"I know a lot of professional footballers," Hughes said. "The idea was they were going to promote it for me … but it doesn't look like I need them to now."