Pallone says that he lost his job as an information security officer at Banco do Brasil in March after exposing security breaches which left the firm open to money laundering and fraud.

The staffer had joined in May 2012 on a 12 month fixed term contract but the bank decided not to renew it. According to the Daily Mail, the day after he was told he was being let go the IT man - who is suing the bank for whistleblowing - sent out an e-mail to colleagues warning them about misusing work equipment.

Says Pallone in his statement to the Central London Employment Tribunal: "In accordance with the respondent's own policies and procedures and without citing any names or details, I simply sent out an email reminding all users of the respondent's policy regarding computers and the prohibition of downloading and storing indecent imagery."

Banco do Brasil says that Pallone knew about the photos on the manager's laptop in December but only sent out the e-mail - which went to offices across Europe - when he knew he was being let go in a bid to "wreak revenge".

Once the e-mail went out, he was put on immediate gardening leave, banned from entering the bank's office and had his access to networks cut off.

"I found the whole episode distressing and humiliating. I was prohibited from accessing the respondent's premises even to collect my own personal belongings or say farewell to the colleagues that I had worked with," says Pallone in his statement.

Pallone says that in his short time at the Banco do Brasil London office he found "major systems errors" and claims that the bank's Oracle Flexcube technology platform was riddled with bugs. He says that when he reported these problems, arguing that they breached FSA rules, his concerns fell on "deaf ears".

However, the bank denies that he was let go for raising these issues, insisting that his contract was not renewed because IT problems had been addressed and money needed to be saved.