A newly published survey has revealed that managers are looking to increase the number of staff employed to monitor internal emails.

Of the larger companies surveyed over a third already employ people to read internal emails and check that email policies are being adhered to, and the figure rises to 40 per cent with the largest enterprises.

Over a quarter are planning to increase the number of people they employ to carry out such snooping.

"These results indicate the rising prominence of outbound email as a source of risk for corporations," stated the report.

"Specifically, companies are most concerned about ensuring that email is not used to leak company trade secrets or other forms of intellectual property."

Other concerns include compliance with corporate email policies and financial disclosure regulations, and ensuring that email cannot be used to leak confidential internal memos.

The survey, carried out for email security company Proofpoint, also found that 27 per cent of respondents had fired an employee for breaking email policy in the past year, and over half had disciplined employees for the same reason.

More than one in 10 firms had handed over employee emails to a court or regulatory body.