According to a report by the Henry Jackson Society security think-tank at least three Al Qaeda-linked networks, which were planning terror attacks against Britain, have changed their tactics after the former contractor from the US National Security Agency (NSA) leaked about 1.7 million classified documents to the media,

The report says the Al Qaeda affiliates have altered their communications, using human couriers instead of email and mobile phones.

Report author Robin Simcox was quoted as saying by Daily Mail that while the focus has been about the so-called mass surveillance by GCHQ and the NSA but these leaks have allowed extremist groups and jihadists to look at our capabilities – what we can and can't do – which has given them a great insight.

Simcox however said that it was astonishing the focus of the Snowden affair has been more on the shortcomings of our intelligence agencies and not the fact Snowden has helped terror suspects drop off the radar."