Image copyright PA Image caption A number of banking scandals have tarnished the reputation of the City

The most common phrases used by fraudsters in emails are "cover up", "write off" and "illegal", research has found.

Rogue traders can be caught by searching for key words in their emails scanned by software developed by accountants Ernst and Young, using US Federal Bureau of Investigation tools.

The software found there are more than 3,000 key terms used in emails.

"Nobody will find out" is another common phrase the researchers found.

The software can alert management about suspicious trends.

"Most often such email traffic is only seized upon by regulators or fraud investigators when the damage has been done," said Rashmi Joshi, director of Ernst & Young's fraud investigation unit.

TOP 10 MOST COMMON PHRASES USED IN FRAUD EMAILS Cover up

Write off

Illegal

Failed investment

Nobody will find out

Grey area

They owe it to me

Do not volunteer information

Not ethical

Off the books Source: Ernst and Young

"Firms are increasingly seeking to proactively search for specific trends and red flags - initially anonymously - but with the potential for investigation where a consistent pattern of potential fraud is flagged."

'Very revealing'

The software uses an analysis of language, statistics, and call data.

"The language, which is a mix of accounting phrases, personal motivations and attempts to conceal, are very revealing," Ms Joshi said.

A wave of banking scandals has undermined faith in the banking industry over the past few years.

Both Barclays and UBS have been fined for attempts to rig Libor, a benchmark rate used for more than $300 trillion worth of loans and transactions. In addition, reports have said at least 15 banks globally are being investigated for possible Libor manipulation.

Meanwhile, UBS was also fined over failings that allowed a trader, Kweku Adebole, to lose $2bn (£1.2bn) in speculative trading. Mr Adebole was jailed for seven years for fraud after a trial in London.