HUNDREDS of Clyde workers are fitting out Britain's biggest ever warship as the countdown begins to its launch.

In just 100 days HMS Queen Elizabeth will leave the dry dock at Rosyth following a naming ceremony just five years after the first steel cut took place at the Govan shipyard.

The warship - three times the size of traditional carriers - will undergo extensive sea trials to make sure she and her crew are battle ready to enter service in 2016.

HMS Queen Elizabeth has been built in sections at yards across the UK with giant steel blocks taken by barge on sea to Rosyth for final assembly.

Hundreds of workers at the Clyde yards of Scotstoun and Govan have been involved in the construction not just in Glasgow but also at the East Coast yard.

The super-sized carrier - it will cover four acres - has now been put together with just one huge lift for planes and helicopters waiting to be secured.

Today, 400 tradesmen and women from the Glasgow yards are helping get HMS Queen Elizabeth ship shape by assisting with fitting her out in readiness for the official naming ceremony, performed by the Queen, on Friday, July 4.

Once over, thousands of gallons of water will be released into the dry dock.

The so-called "flood up" will take place weeks later.

The carrier will then leave the dry dock which will be prepared for the hull section of a second and last super-sized carrier, HMS Prince of Wales.

Hull sections for it are also being built on the Clyde.

The Prince of Wales is due to enter service in four years. Both carriers have a price tag of £5.2billion, although there is speculation that final costs will be nearer £7bn.

The carrier programme is being spearheaded by an alliance involving the Ministry of Defence, BAE Systems - owners of the Clyde yards - Babcock and Thalis UK.

Programme director Ian Booth of the Aircraft Carrier Alliance (ACA) said: "The excitement around the naming of HMS Queen Elizabeth continues to grow and the daily countdown will add further momentum to this.

"We are working hard to prepare the ship and plan the celebrations which will mark this significant phase in the programme to deliver the nation's flagships.

"Getting to this point is testament to the hard work and commitment of everyone involved in the programme, from the teams across the ACA to our suppliers in every region of the country."

Each carrier weighs 65,000 tonnes, is taller than the Niagara Falls and is 280 metres long - the equivalent of three football pitches. They have 12 decks and 3000 compartments.

BAE engineers have devised a mobile phone app to help workers navigate their way around what is said to be the most complex workplace in the world. Each compartment has a QT code which is scanned by app users before they type in their destination. The applica-tion then displays the best route.

Mick Ord, managing director of BAE's navy ships division, said: "These are the largest and most powerful warships ever constructed for the Royal Navy so we need to keep find-ing smarter, safer and more efficient ways of working."