The Ministry of Defence (MoD) will first be working to locate the jet. Afterwards, it has to decide whether to recover the aircraft, or any pieces if it has broken up.

The technology exists for such a recovery, even given the depth of water. The US has considerable experience of this, having suffered a number of “ditchings” from aircraft carriers.

If a recovery operation is launched, a dedicated salvage platform will need to be located and contracted for the task, given that the MoD does not own such equipment.

However, it is not known how long any salvage operation will take. It will not be swift and will be dictated by the location of any salvage platform.

However, while the UK is aware that Russia is watching, on Friday night Navy sources sought to play down the threat, insisting that Russian Kilo-Class submarines that could be used to search for the jet are located in the Black Sea and are not capable of diving to 1.24 miles.

The MoD does not comment or speculate on matters that could affect operational security, but it is thought likely the swift recovery of the aircraft will be a priority.

Britain will likely call on allies to support the logistics of any salvage operation.