After a case brought by human rights group Liberty, appeal judges found that the preceding Data Retention and Investigatory Powers Act 2014 (DRIPA) - which ultimately became the Snooper's Charter - failed to offer adequate protection to people's data.

The judges were rather worried that private data could be shared between different agencies without sufficient oversight.

Three judges looking at the case brought by Liberty on behalf of MP Tom Watson, said that DRIPA's lack of safeguards meant that it was "inconsistent with EU law". Watson welcomed the ruling, saying: "This legislation was flawed from the start. It was rushed through parliament just before recess without proper parliamentary scrutiny. The government must now bring forward changes to the Investigatory Powers Act to ensure that hundreds of thousands of people, many of whom are innocent victims or witnesses to a crime, are protected by a system of independent approval for access to communications data. I'm proud to have played my part in safeguarding citizens' fundamental rights."

Liberty said that the ruling shows, once again, that the UK government's mass surveillance program is unlawful. Group director Martha Spurrier said: "This judgment tells ministers in crystal clear terms that they are breaching the public's human rights."

The government has not yet indicated how it intends to respond to the ruling. It must have hoped that getting out of the EU would mean that it could treat its citizens how it liked.  It might just wait for Brexit to go through and then bring it back.