The Queen has declared a flagship aircraft carrier built in Rosyth as "the best of British" as it joined the Royal Navy fleet.

The 65,000-tonne HMS Queen Elizabeth is the largest and most powerful warship ever built in the UK.

She left Rosyth Dockyard on the Firth of Forth in June and on Thursday the Queen visited her namesake at Portsmouth Naval Base to see her officially join the fleet.

After boarding the £3.1bn carrier using a specially-installed lift she gave a speech in front of 3700 guests describing it as "the best of British innovation".

She said: "We are gathered here in Portsmouth today just a short distance from HMS Victory, a flagship of our seafaring past and a reminder of the debt we owe to the Royal Navy, which for more than 500 years has protected the people of this country and our interests around the world.

"Like HMS Victory, HMS Queen Elizabeth embodies the best of British technology and innovation, a true flagship for the 21st century.

"The most powerful and capable ship ever to raise the White Ensign, she will in the years and decades ahead represent the country's resolve on the global stage."

Construction work on HMS Queen Elizabeth began in 2009 at six shipyards in Glasgow, Rosyth, Appledore, Hebburn, Portsmouth and Birkenhead.

Sections of the 920ft-long carrier were then assembled at Rosyth Dockyard from 2011.

During the ceremony on Thursday, the Queen was presented with an 8ft cake replica of the carrier.

The confection weighed almost 24 stone and was made by Scottish cake-makers 3D Cakes.

Following Royal Navy tradition, it was cut by the captain's wife and the youngest member of the ship's company.

Warrant officer first class William Shepherd said it would take pride of place in the Royal Navy's culinary school.

He said: "I've been in the Royal Navy 28 years and I genuinely believe this is the best commissioning cake I've ever seen."