Britain is ‘woefully’ short of the capabilities needed to protect its undersea cables from a potential Russian attack, experts have warned, amid fears Moscow will deploy a ‘secret weapon’ to sabotage vital infrastructure.It comes as Nato allies caught Russian submarines training to unleash a secret weapon designed to disable critical undersea cables without leaving any fingerprints.The clandestine Russian operation, described by two Western officials, was carried out by Moscow's GUGI undersea warfare directorate, which used deep-sea submersibles to simulate the deployment of the sophisticated technology.A joint operation involving Britain, Norway and the US tracked and confronted the Russian vessels at sea, the two officials said.The vessels were prevented from completing their exercise and eventually left the area.Security expert and journalist Philip Ingram has said the UK's military capability is 'woefully short to help protect the critical undersea cables that are going through UK waters'.'The UK doesn't have enough power to stop a determined Russian attack,' he added.'The one thing that the Russians have maintained a very, very strong military capability with is their submarine service and the fleet that they put out into the North Atlantic.