Fears have been raised that Britain’s largest ever warship could be vulnerable to cyber attacks after it emerged it appears to be running the outdated Microsoft Windows XP.

As HMS Queen Elizabeth left its dockyard for the first time to begin sea trials, it was revealed the £3.5billion aircraft carrier is apparently using the same software that left the NHS exposed.

Screens inside a control room on the ship, which is the largest vessel ever built for the Royal Navy, reportedly displayed Microsoft Windows XP - copyright 1985 to 2001.

But Michael Fallon, the Defence Secretary, insisted the ship's systems were safe because security around the computer software on the aircraft carrier is "properly protected".