Think before you hit that "send" key.

With emails now a compliance minefield, the big corporations in the US and Britain are now bringing in snoops to monitor and vet emails at the workplace.

Research conducted by Forrester Consulting for email security firm ProofPoint has found that nearly four out of 10 US companies with 1,000 or more employees hire staff to read or analyze outbound email. And 44 per cent of companies with more than 20,000 workers brought in snoops for this purpose.

The study of US corporations found that about one in three firms have sacked an employee for violating email policies in the past 12 months and more than half had disciplined employees for violating email policies in the past year.

Companies estimate that more than one in five outgoing emails contain content that could be a legal, financial or regulatory risk and more than a fifth were hurt by improper exposure or theft of customer information. More than one in four were ordered by a court or regulatory body to produce employee email in the last year.

Similar figures have come out of Britain.