Image copyright PA Image caption GCHQ: Has the power to gather MPs' communications data

MPs have no protection from having their communications read by UK security agencies, a tribunal has said.

Green Party politicians Caroline Lucas MP and Baroness Jenny Jones argued a long-standing doctrine protecting MPs' communications was being breached.

But in a landmark decision the Investigatory Powers Tribunal said the so-called "Wilson Doctrine" was no bar to the incidental collection of data.

Ms Lucas said the decision was a "body blow" for democracy.

The Wilson Doctrine came into being in 1966 when the then Labour prime minister, Harold Wilson, gave assurances to MPs that their phone calls would not be intercepted without him knowing - and that he would tell Parliament of any change in that policy.

'Political statement'

The doctrine has been repeatedly reaffirmed, including by Prime Minister David Cameron.

However, Ms Lucas, Baroness Jones and former MP George Galloway argued that GCHQ was acting outside the long-standing doctrine by bulk collecting communications data from the internet, which would inevitably include correspondence between parliamentarians and their constituents.

Analysis

Image copyright Science Photo Library

By Dominic Casciani, BBC Home Affairs correspondent

The IPT couldn't have been clearer about the worthlessness of the Wilson Doctrine had they shoved a copy of Hansard from 17 November 1966 into the courtroom shredder.

But while their ruling may come as something of a shock to some MPs - it's been abundantly clear for almost a decade that the doctrine's days were numbered.

Wilson gave his guarantee to MPs when the UK refused to admit that it even had spooky agencies working in the shadows. Today, there is legislation that sets out how agencies can intercept communications.

The existence of those laws has led to repeated questions about whether Wilson is still needed. MPs like Caroline Lucas argue that it still is because of the sensitive work that some parliamentarians do in holding the executive to account.

"We are satisfied that the Wilson Doctrine is not enforceable in English law by the claimants or other MPs or peers by way of legitimate expectation," said the IPT.

"The Wilson Doctrine has no legal effect, but in practice the agencies must comply with... their own guidance.

"The regime for the interception of parliamentarians' communications is in accordance with the law."

Image copyright PA Image caption Green MP Caroline Lucas said she was disappointed with the decision

The landmark challenge largely focused on the so-called Tempora programme - the harvesting of communication data from the internet first revealed by American security contractor Edward Snowden.

The IPT did not mention Tempora by name but said "incidental" collection of MPs' data would not constitute a breach of the Wilson Doctrine, which was largely a political statement that could not be relied upon in expectation of special treatment.

The prime minister's official spokeswoman said the government "welcomed" the decision saying the Wilson Doctrine maintains its status as a "long standing political commitment" but said it "shouldn't undermine the ability of the intelligence agencies to act in a targeted way".

Conservative MP Dominic Grieve, chairman of the Intelligence and Security Committee, said: "This is exactly what I expected. Nothing in this surprises me. It seems to me to be a reasoned and sensible judgement."

'Blanket surveillance'

But Ms Lucas said she was disappointed with the decision and called for new legislation to protect constituents' communications.

"This judgement is a body blow for parliamentary democracy," she said.

"My constituents have a right to know that their communications with me aren't subject to blanket surveillance - yet this ruling suggests that they have no such protection.

"Parliamentarians must be a trusted source for whistleblowers and those wishing to challenge the actions of the government. That's why upcoming legislation on surveillance must include a provision to protect the communications of MPs, peers, MSPs, AMs and MEPs from extra-judicial spying.

"The prime minister has been deliberately ambiguous on this issue - showing utter disregard for the privacy of those wanting to contact parliamentarians."

The IPT panel, headed by two senior High Court judges, said parliamentarians had the same legal protections as anyone else against unwarranted and unjustified interception of their communications - and only journalists and lawyers had greater protections under human rights law.