The case, Big Brother Watch & Ors v UK (Applications 58170/13, 62322/14 and 24960/15) was brought against the UK government by Privacy International and 15 other applicants after whistleblower Edward Snowden revealed mass surveillance programmes by GCHQ in the UK and US intelligence agencies in 2013.
The decision adds a requirement of prior independent or judicial authorisation for bulk interception of data.
Ilia Siatitsa, acting legal director at Privacy International, said it was ‘an important win for privacy and freedom for everyone in the UK and beyond.
‘The court reiterated that intelligence agencies cannot act on their own, in secret and in the absence of authorisation and supervision by independent authorities.’