Proposals for a new law governing state agencies’ interception of communications lack statutory protection for legal privilege, it emerged today as the government published a long-awaited draft investigatory powers bill.

The Law Society said it was ‘concerned by the absence of explicit protection’.

The draft bill, introduced by the home secretary Theresa May today, proposes to overhaul the hastily introduced Regulation of Investigatory Powers Act 2000 as well as provisions of the Police Act 1997 and the Justice and Security Act 2013.

It contains controversial measures to require internet companies to store details of users’ web browsing for a year. It will also set up a new regulatory regime under a new commissioner, former Court of Appeal judge Sir Stanley Burnton (pictured).

Law Society chief executive Catherine Dixon said: ‘We welcome the government’s intention to strengthen the oversight and authorisation framework for investigatory powers through the introduction of a new investigatory powers commissioner.

‘We are however concerned by the absence of explicit protection for clients so that they are able to speak to their legal advisers and receive confidential advice.

‘Legal professional privilege is a vital part of the administration of justice. It protects a client's fundamental right to be candid with their legal adviser without fear that someone is listening in. It does not pose a risk to legitimate investigations because it does not apply when a crime is suspected. In today's draft bill, the government had the opportunity to signal its intention to give appropriate protection to the client-lawyer relationships that a civilised society depends on.

‘We hope that they will reconsider and take the opportunity to safeguard what is widely recognised as a fundamental right.’

The Law Society and Bar Council are jointly campaigning for statutory protection for legal professional privilege. The issue is mentioned in the draft bill, but only in proposals for 'codes of practice' covering what the bill describes 'as a member of one of the sensitive professions'.

Under the codes, police and intelligence agencies 'must make a compelling case to the secretary of state explaining why it is necessary and proportionate to seek the warrant and what additional protections they will apply to any particularly sensitive material obtained, such as that which is legally privileged. They must also notify the [investigatory powers commissioner] that sensitive material has been obtained as soon as it is practical to do so'.

May told parliament that the bill ‘will establish world-leading oversight to govern an investigatory powers regime which is more open and transparent than anywhere else in the world.’

However civil liberties campaign group Liberty said that the draft bill does not contain powers for substantive judicial approval of surveillance warrants. ‘It instead proposes a highly limited form of judicial review which will – in practice – be a rubber-stamping exercise.’

The Home Office said the draft bill will now go through full pre-legislative scrutiny before a revised bill is laid before parliament in spring 2016.