The BBC’s Investigations Service, an internal unit of the corporation, has apparently accessed the email accounts of BBC staff 140 times since 2009.
The email probes were part of enquiries into alleged criminal activity including assault, fraud, theft, bribery and harassment as well as for investigations into computer misuse, information leaks, malicious communications and security incidents.
Staff would have been unaware that their emails were being monitored, with the BBC explaining that its employees understand that monitoring can occur in "exceptional circumstances".
Breaking down the figures, released in a Freedom of Information Act request from the MailOnline earlier this year, there were 30 authorised requests to investigate staff email accounts in 2012, 40 in 2011, 24 in 2010 and 25 in 2009. So far, in 2013, a total of 21 requests have been authorised.
In 2012, four monitoring requests were made for an apparent leak of information, eight were made for computer misuse, six for fraud, one for harassment, one for bribery, two for malicious communication, two for theft and one police enquiry.
In 2011, requests were made for complaints, security incidents, information leaks and assault while requests in 2009 and 2010 were related to computer misuse, fraud and information leaks.
Responding to the publication of the figures, a BBC spokesperson said that it “rarely monitors staff email accounts” and only does so when “it is reasonable, necessary and represents a proportionate response.”