The High Court in London is to hear a challenge by two MPs to the UK government’s surveillance law.
The Data Retention and Investigatory Powers Act 2014 (DRIPA) was fast-tracked through the Commons in only three days last July after the European Court of Justice (ECJ) ruled the existing powers were unlawful.
It permits the UK’s intelligence services to acquire individuals’ phone and internet communications.
However, Labour’s Tom Watson and the Conservative minister David Davis are to argue the law is incompatible with human rights legislation.
At the time the law was being considered the government said the UK’s power to combat terrorism and crime would be seriously affected by the ECJ’s ruling, making the new law necessary.
Ministers said the act would merely retain existing powers which required companies to keep communications data for a year.
The main political parties, which included at the time the Liberal Democrats, supported the plans.
However, DRIPA has been vehemently opposed by civil liberties campaigners.
Mr Davis and Mr Watson are arguing the legislation lacks proper safeguards and should be reconsidered.
Specifically, they will argue it is incompatible with the right to a private and family life as well as data protection – both afforded by the Human Rights Act 1998 and the European Union Charter of Fundamental Rights.
Emma Norton, legal officer for Liberty, said: “People need to understand just how personal this information is that will be taken and retained and what an intimate portrait of their lives it will create.”
The challenge to DRIPA comes as Home Secretary Theresa May outlines new measures for police and intelligence agencies to monitor internet and phone use.
She first attempted to introduce a similar bill in 2012, which became known as the “Snooper’s Charter”.
However, these attempts were rebuffed by coalition partners the Liberal Democrats.