What are the cables linking Somerset to New York?

The world's internet traffic mostly runs through undersea data cables, some of the main ones connecting the UK and Ireland to Canada and the USA.

One of those cables, the EXA Express, starts in New York and comes ashore in Brean on the Somerset coast.

The EXA is 4,600 km (2,858 miles) long, was laid in 2015, and is crucial to the financial centres of the City of London and Wall Street.

The Ministry of Defence has claimed Russia recently sent spy submarines to study some of the cables. So what are they, and why are they so important?

The UK is dependent on its undersea cables and pipelines for its data and energy.

There are around 60 which come ashore at several points along the UK coastline, particularly around East Anglia and South West England.

More than 90% of the UK's day-to-day internet traffic travels via these undersea routes.

Alan Mauldin, research director at TeleGeography, a research organisation that collects and analyses data across the telecoms industry, said submarine cables carry voice calls, e-mails, video and stock transactions.

"It is very common to think you have a mobile phone and it goes wirelessly over the air somehow through the world," Mauldin added.

"It goes to the next cellphone tower and then it goes through fibre cables on land and when it needs to go to another continent, it goes on submarine cables.

"Satellites are important to reach remote locations. The capacity carried by submarine cables dwarfs what can be carried by satellites."

In 2022, 200,000 Russian troops invaded Ukraine, triggering years of war with an estimated million people killed or wounded between both sides.

Nato believes Russia is also waging another war, an undeclared one, something called "hybrid warfare" and that the target is Western Europe itself, with the aim of punishing or deterring Western nations from continuing their military support for Ukraine.

Three Russian submarines carried out a month-long covert operation above cables and pipelines in the Atlantic according to the MOD - something the Russians have denied.

Defence Secretary John Healey said the vessels were monitored around the clock and there was no evidence of any damage to UK infrastructure.

Potential sabotage to cables should be seen "as not just an isolated phenomenon" but as part of "Russia's much more holistic programme of targeting communications infrastructure and critical infrastructure overall", according to Keir Giles, a Russia expert at Chatham House.

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