BBC News' Ishbel Matheson reports

However, the Grand Princess already has a troubled history.

Originally scheduled for launch two weeks ago, the Italian building company failed to meet their deadline much to the disappointment of its British owners, P&O Ferries, and over 2,000 passengers.

David Curtis, of What Cruise? magazine, describes the Grand Princess and cruise holidays

Now, with work completed, the Grand Princess, which boasts five swimming pools, an art gallery, two theatres and a nine-hole golf course, will sail from Istanbul to Barcelona on her inaugural passenger trip.

The ship is taller than London's tallest building, Canary Wharf

The 109,000-tonne ship will carry 2,600 passengers, who have paid between £2,000 and £5,000 per cabin, on an experience billed by her owners as "the last word in cruise luxury".

Gill Haynes of P&O Cruises described just what can be expected by all those who sail in her: "Despite the overwhelming physical size of the ship, the Grand Princess has a very warm and homely feel inside, which gives passengers the choices available on big ships as well keeping the intimate atmosphere of being in a smaller vessel."

Size matters

The Grand Princess will be the world's largest cruise ship afloat, and at a cost of £265 million, she is also the most expensive passenger vessel ever built.

Every possible luxury

Her mammoth size measures 951 feet long, 201 feet high and 159 feet wide and is the work of the Italian shipbuilding company, Fincantieri in Molfalcone.

David Curtis, editor of What Cruise? magazine, says huge cruise liners reflect how shipbuilding today has changed since the days of the Titanic when travelling by ship was often the only means of getting from A to B.

"The cruise ships now are built primarily to give entertainment and pleasure to the passengers and a huge amount of space is given over to this. There is a lot of emphasis on providing nightclubs and shows. For example, the auditoria on the Grand Princess are bigger than the size of the London Palladium, " says Mr Curtis.

Cruise holidays are also one of the fastest-growing sectors of tourism. In America, for example, 30 per cent of people who take long-haul holidays choose a cruise.

In Britain, cruise holidays reached new heights of popularity last year with around 750,000 people spending their holidays at sea - more than those taking ski holidays.

As a result, business has been booming in some of Europe's shipyards. The Kvaerner Masa shipyard in Helsinki, Finland, has so far this year secured contracts worth over £1bn ($1.6bn) to build cruise liners - and it seems the maxim "the bigger the better" holds true for today's ships.

Losing the stereotype

According to Mr Curtis, luxury cruise liners like the Grand Princess also undermine the traditional view of the cruise holiday passenger - "the blue rinse brigade", over the age of 50, retired and ready to devote time and money to luxury and relaxation.

A lot of the entertainment facilities on the Grand Princess are aimed at attracting younger passengers: there is the first Virtual Reality centre at sea, a disco suspended 150 feet above the stern as well as the largest ever on-board casino.

The Grand Princess also offers something for the passenger looking for a bit of romantic adventure on their cruise holiday - with the first ever wedding chapel on board a ship, passengers can be married at sea by the Captain and combine the wedding ceremony, reception and honeymoon all into one.