THE largest and most powerful ship ever built for the Royal Navy has left its construction dock for the first time.

HMS Queen Elizabeth, a 280m, 65,000 tonne aircraft carrier, set out from Rosyth on the Firth of Forth yesterday.

The £3 billion vessel, which is set to be the country’s flagship, and its 700-strong crew are ready to undertake maiden sea trials over the summer.

However, getting the carrier out to sea involved one of the most delicate manoeuvres of the six-week trials.

Navigators, pilots and tug boats had the slimmest of margins to deal with to guide HMS Queen Elizabeth out of the Rosyth basin where it was assembled.

At high tide the ship was taken through a narrow gate avoiding the dock walls by inches, while under the water line there was just half a metre between the bottom of the ship and the sea bed.

Commanding officer Captain Jerry Kyd said: “We have to be very careful, but you practise it and drill it and rehearse it to make sure we could do it safely in a timely fashion because the tide waits for no man.”

nce in the Forth, the carrier had to wait for the tide to lower to pass under the Firth’s famous bridges.

Ten thousand people worked on the construction of the ship, made up in sections at yards around the UK and transported to Rosyth, where it was assembled.

The Commander of HMS Queen Elizabeth has strongly defended the need for such a ship, with questions raised over its cost and relevance in a changing world.

Captain Kyd insisted that despite its size it remained an “incredibly flexible tool” that was not only about war fighting, but deterrence, political signalling, disaster relief and humanitarian assistance.

Rapid developments in technology have led to discussions over the future of defence, with the advent of unmanned drones and cyber warfare, but the commanding officer believes HMS Queen Elizabeth and sister ship HMS Prince of Wales will be good value over the next 50 years.

Cpt Kyd said: “These ships are expensive, absolutely, but look at all the major nations around the world, they all have an aircraft carrier capability. 

"There is nothing that is invulnerable, whether it’s a city, a car, an individual or a ship. We are not shy in the military to understanding risks and how to mitigate that in the theatre of war."

The second ship in the class, HMS Prince of Wales, is being fitted out in the dock and staff will be able to look on as its sister ship sets sail for the first time.

The sea trials will take place in the North Sea before the carrier returns to Rosyth for further checks and any adjustments.

Captain Kyd went on: “After that we’re going back out for a further three weeks to test the ship on the more war-fighting capabilities - the radars, all the ship’s sensors, radios and things like that.

“At the end of that period we know that all the basics work. She’s done her test drive and after that we will go down to Portsmouth, the ship’s home, and get her finally ready to join the Royal Navy fleet, hopefully at the end of the year.”