Russia may sabotage a North Sea pipeline from Norway to the UK this winter which would cut crucial supply, it has been reported.
Western intelligence is said to be worried Moscow could target the 5,500-mile Langeled pipeline which transports a fifth of the UK’s natural gas supply.
The leaks left areas in mainland Europe with a decreased gas supply after delivery was reduced or halted by Russia due to the damage.
Watch: Underwater footage shows damage to Nord Stream pipeline
Dwindling flows of gas from Russia, which once supplied 40% of Europe's needs, have left the European Union struggling to unite over how to respond to surging prices that have deepened a cost-of-living crisis for families and businesses.
There are fears Russian president Vladimir Putin could use the energy supply as a weapon as he continues as his war in Ukraine continues to falter.
“Sabotage is the next step if they want to escalate by attacking Britain's critical energy infrastructure because we are so fragile,” said a NATO source, according to the Mail.
“And it's no coincidence that Britain has been one of Ukraine's biggest backers.”
Stale Ulriksen, researcher at the Royal Norwegian Naval Academy, added: “As a strategic target for sabotage, Norwegian gas pipelines are probably the highest value target in Europe.”
The Kremlin said allegations of Russian responsibility for sabotaging the Nord Stream pipelines were "stupid" and the country's defence ministry has accused representatives of the British Navy of being responsible.
The defence ministry did not give evidence for its claim.
Langeled pipeline operators Gassco are reportedly on a high-security alert after drones were spotted above gas infrastructure in Norwegian waters and a number of Russians were arrested.
Sweden has ordered additional investigations to be carried out of the damage done last month to the two Nord Stream pipelines, the prosecutor in charge of the case said in a statement on Friday.
Sweden and Denmark have concluded that explosions caused four leaks on Nord Stream 1 and 2, but have not said who might be responsible.
World leaders have called it an act of sabotage.
"I've decided together with the security police to carry out a number of additional investigations at the scene of the crime," lead prosecutor Mats Ljungqvist said.
Sweden's armed forces said this week that they were carrying out an independent investigation of the seabed around the leaks with minesweepers.
Nord Stream AG, the operator of the leaking Nord Stream 1 gas pipeline, sent a chartered ship to waters off the coast of Sweden to survey the damage for the first time on Thursday.