The service’s longest serving nuclear-powered hunter killer sub is due to be decommissioned after nearly 30 years of service.

The vessel, base ported in Devonport, operated as one of the Cold War “warriors”, a Navy spokesman said.

“Out of sight and mind, she deployed for long, secret and often dangerous missions out into the Atlantic,” he added. “She patrolled for months at a time searching for and stalking her enemies.

“Renowned for her stealth and many successes she enjoys a strong reputation to this day.”

The sub returned home tonight after completing the first deployment by a Royal Navy nuclear-powered submarine to Australia in seven years.

HMS Tireless had also been assisting in the search for missing Malaysian Airlines flight MH370.

HMS Tireless was launched in 1984 and commissioned a year later.

She surfaced at the North Pole in 1991, 2004 and 2006, and between 2010 and 2011 took part in a 10-month deployment, the longest continuous deployment by a UK nuclear-powered submarine up to that date.

This year she has been on East of Suez deployment, which included her searching for Flight MH370.