Britain's ability to defend itself has been called into question after an investigation found Navy warships are so loud they can be heard 160km away by Russian submarines.
Rear Admiral Chris Parry, a former director of operational capability for the Ministry of Defence, said the 1 billion ($1.7b) Type 45 destroyers are "as noisy as hell" and sound like "a box of spanners" underwater.
It comes amid warnings that years of defence cuts and expensive procurement contracts with a small number of large defence firms has left the military with an "existential minimum" amount of equipment.
The Ministry of Defence spent 3.5b on each of the Army's Ajax tanks, but they are unable to fit on board transport aircraft without needing to be dismantled, according to a report by the Sunday Times.
A further 1.2b was spent on 54 Watchkeeper reconnaissance drones, which have not entered frontline service for 12 years.