In fact, a secret Government Communication Headquarters (GCHQ) cable map obtained by Mr Snowden shows the Hibernia Atlantic line as it navigated past Ireland prior to its making landfall at Coleraine.

The document warns “several new cable systems [have been] introduced (just in 2010)” and “we need to maintain our investment in the access footprint in order to keep up.”

Documents, published by Glenn Greenwald’s The Intercept also suggest GCHQ has been secretly operating a program called KARMA POLICE to record the website browsing habits of “every visible user on the Internet.”

The classified files suggest GCHQ has been collecting data about people’s visits to the adult website YouPorn, search engines Yahoo and Google, Facebook, Reddit and news sites operated by CNN, BBC, Channel 4 News and Reuters.

The agency also monitored more than 200,000 people listening to online radio shows, according to the Snowden documents, and spied on individuals visiting the New-York-based anti-secrecy website Cryptome.

According to The Intercept KARMA POLICE is a project that enables GCHQ to monitor people’s website browsing histories.

It was designed to allow GCHQ view “(a) a web browsing profile for every visible user on the internet, or (b) a user profile for every visible website on the internet.”

One document describing the function of KARMA POLICE explains that it can be used to “enter a website of interest and this will tell you who has been looking at it.”

Another project called MUTANT BROTH is used to analyse vast amounts of tiny internet data files known as cookies, which identify and sometimes track people browsing the internet, often for advertising purposes.

Another GCHQ tool, SOCIAL ANTHROPOID, can be used to search through troves of metadata on emails, social media interactions, instant messenger chats, mobile phone locations, text messages, and calls made on the internet using ‘Voice over IP’ technology such as Skype.