Nuclear-powered submarine HMS Tireless was launched on 17 March 1984 and holds a crew of 130, plus 18 officers.
HMS Echo will help search for debris from the plane on the water surface. An MoD source told the BBC the vessel had “advanced underwater search capabilities, but the task in hand remains a tall order and the search area immense”.
“Her deployment is being co-ordinated closely with our Australian and US colleagues.”
The submarine will listen for ultrasonic “pings” from the plane’s black box, which continue to be broadcast for about 30 days after take-off.
Even still, experts predict the hunt won’t be easy.
Earlier on Tuesday, Air Chief Marshal Angus Houston – the man co-ordinating the search from Australia – said the hunt was the “most challenging” ever seen and could take weeks.
Floating debris has been found in recent days, but it’s not believed to belong to the missing plane.