Its call follows the publication in February of a report by Her Majesty’s Inspectorate of Constabulary (HMIC) on the use of undercover police officers such as Mark Kennedy, who worked undercover for seven years to infiltrate protest groups.

Legal professional privilege (LPP) has been debated during the passage of the Protection of Freedoms Bill in the House of Lords. Baroness Hamwee proposed an amendment suggested by the Bar Council that would protect LPP in all circumstances except where it is “being used to further a criminal purpose”. This would have brought the Regulation of Investigatory Powers Act 2000 (RIPA) in line with existing legislation. However, it was opposed by Home Office Minister, Lord Henley, and withdrawn.

Michael Todd QC, chairman of the Bar, said: “[This] report by HMIC emphasises the need for stricter and more coherent rules around the surveillance of individuals by the state.

“Unfortunately, it does not address a key concern raised by the case of DC Kennedy: that he may have been privy to legally privileged communications between fellow defendants and their lawyers and could have passed that material to the Crown.

“It is extremely disappointing that the government has not so far taken the opportunity presented by the Protection of Freedoms Bill to reassert the fundamental right of an individual to consult their lawyer in private. This is a right which was unintentionally eroded by RIPA, as confirmed by the 2009 House of Lords judgment in Re McE.”

In Re McE, the Law Lords held that the police could lawfully use covert surveillance to listen in on lawyer-client communications, even those “communications which are normally covered by legal professional privilege”.

“RIPA contains no express provision about legal privilege, so the issue was not debated when the legislation was considered by Parliament,” said Todd.

“Whenever Parliament has had an opportunity to consider LPP, it has consistently voted to protect it, subject to the provisions contained within the proposed New Clause. The government appears to want to continue to be able to erode this fundamental human right for investigatory purposes. In our view, this is unacceptable.”