The technical specs are certainly impressive: 17 decks (the equivalent of a 23-storey building); a length of 1,132ft (that's almost four football pitches from bow to stern); and space for 2,620 passengers and 1,253 crew. The folio of onboard facilities includes a towering six-deck-high lobby, a traditional-style ballroom, a vast spa and a 493-seat planetarium. The ship will also feature the world's largest permanent onboard art exhibition.

The man behind the exuberant interior of Cunard Line's first liner for 34 years is Andy Collier of London-based SMC Design. As the ship's lead architect, Collier has been responsible for everything from the general planning of the ship to the decor of the rooms, right down to the doorknobs.

''It really was a dream job for me to have that level of involvement,'' says Collier, who has also done refits for the QE2, the QM2's sister ship. ''It is undoubtedly the biggest project I have worked on. It has been a huge task and one that has been four and a half years in the making.''

For Collier, reflecting the history of Cunard, which owns the QM2, formed an integral part of the ship's design. ''We looked at photographs of the old liners such as the Normandie, the Ile de France and the original Queen Mary,'' he says. ''The style of design was very art deco-ish and sort of 'decorative thirties', as they called it. We decided that was the way we wanted to go with it, but at the same time we didn't want to slavishly copy it. We wanted to take the good elements from that period and bring them right up to date.''

Other key features of the ship include the Britannia Restaurant, spread over two tiers and with spectacular sweeping staircases, and the funkier-edged design of G32, the onboard disco which gets its name from the ship's hull number and is decorated in a futuristic-meets-industrial chic - all silvers, greens and purples.

''In the main public rooms, such as the lobbies, dining rooms and bars, we were keen to make sure we featured traditional elements which referred back to the golden age of travel,'' says Collier. ''Back then, though, they didn't have things like discos, 24-hour lidos or such huge health spas as we have now, so we made a conscious decision to look at those rooms afresh and make them different in their own right, but at the same time still tie in with the rest of the ship.''

Collier clearly tries not to play favourites, but, when pushed, names the Queens Room as being among his fondest onboard creations. ''It is the biggest open space on the ship and a traditional ballroom in a grand sense,'' he says. ''Because it is very high, wide and long, it shows off the volume of the ship. The room is very traditional in the way it is decorated and reminiscent of an English country house with its swaged-draped curtains and huge chandeliers. There are also some phenomenal lighting effects which can be achieved. I think that, particularly at night, it will be a very 'wow' room.''

In aesthetic terms, however, reactions to the ship have been mixed. The distinctive red, black and white livery of the Cunard Line may be there, but for many the ship lacks the eminence of its predecessors. While the QM2 emulates many aspects of a traditional liner - in particular the sleek and dynamic lines of the hull - the upper section bears all the hallmarks of a modern cruise ship, not least in the stacked high-rise of balconies. The ship's interior has also come under fire from purists who mourn the elaborate decorative flourishes associated with the grandeur of old-style cruising. Indeed, some critics have already labelled the QM2's veneered walls and plastic murals more reminiscent of a Las Vegas casino than a classic ocean liner.

But, as Collier points out, modern safety regulations - including new Solas (Safety of Life at Sea) guidelines that are set to come into force from 2010 - stipulate the type of materials which can be used onboard today's ships. They have given him and his team something of a design headache.

''When the original liners were built there weren't really that many restrictions on the materials that could be used,'' he says. ''Since then there have been an awful lot of lessons learned - the majority the hard way, unfortunately. Now all walls, floors and ceilings must be of a fire-rated material. That very much restricts us, as designers, in the type of materials we can use. But safety is a paramount concern, particularly when a liner is out at sea, three days away from anywhere.''

Gary Buchanan, a cruise-ship specialist and maritime historian, admits he was somewhat critical when he first saw the blueprints for QM2. He visited the ship seven times during the last two years while it was under construction in St Nazaire in France, and witnessed the launch at Southampton on Thursday.

''I was initially very sceptical of the design,'' he says. ''Even as I saw the genesis of the ship I still remained slightly dubious that it was going to be the best thing afloat.''

He has been won over, though. ''Critics have called it a Hollywood interpretation of what a grand liner should look like, but I think that it is a little unfair,'' says Buchanan. ''It is recreating - as much as can be done under the constraints of 21st-century maritime design - the elegance and opulence of the original Queen Mary. Some rooms are obviously nicer than others. The planetarium is an absolute masterstroke in design - it is a beautiful room - and the Commodore Club is another room I really like. It is a forward-facing bar, which means you are able to see where you are going, and the shape is also reminiscent of the observation bars on both the Queen Mary and Queen Elizabeth. My favourite room, though, is the Chart Room Bar, which really does hark back to the original Queen Mary. It has high ceilings, lots of space and just exudes charisma.

''As a liner, the Queen Mary 2 is blazing a new trail. It is very much a dual-purpose ship for transatlantic service as well as cruising. It caters to both elements of holidays at sea.

''It has a thick steel hull which will plough through the North Atlantic without too much trouble, but also fulfils the role of a cruise ship, particularly having so many cabins with balconies. When it is in the Caribbean and South America, those will really come into their own.''

Not everyone is convinced, though. Travel industry expert Simon Calder, a presenter for the BBC's Holiday 2004 programme, is among those who believe the golden age of ocean travel is already well and truly over. ''The end of the line for the original Queen Mary, that majestic creation of the Clyde, is a dock in Long Beach, California,'' says Calder. ''In the lifetime since she was launched, a combination of technology and economics has transformed the maritime world. Transoceanic passenger ships have been almost completely superseded by aircraft. Anyone boarding a big ship no longer wants to go from A to B; they want to go from A to A in as much superficial luxury as possible. The result? No role for the great ocean liners, despite their exquisite design and superb craftsmanship. Cunard cannot be faulted for following the market, which is primarily American and appears to demand ever- bigger, glitzier vessels with all the aesthetic values of the East Kilbride Premier Lodge. One day, I hope, imaginative design will count for more than onboard casinos.''

Whatever its detractors say about the QM2, there is little doubt that one of the jewels in its crown is the onboard art exhibition, Maritime Quest. The display, which comprises 127 graphic panels each up to eight metres long, is spread over 500 square metres of the ship's public areas. Again, the emphasis is on the story of Cunard Line, covering key themes such as dining, history and entertainment.

Passengers can pick up a headset from the purser's office and take an audio tour around 60 spots in the exhibition. The tour, lasting around an hour, features a mix of narrative and anecdotes, including first-hand accounts from some of the 700 survivors of the Titanic, plucked in 1912 from the icy waters of the Atlantic Ocean by the Cunard ship Carpathia. Also included are photographs of the many film stars and dignitaries, including Marlene Dietrich, Elizabeth Taylor and Clark Gable, who sailed on the Queen Elizabeth and Queen Mary during the 1930s, 1940s and 1950s. Two books, Stars Aboard and Queen Mary 2: Book of Comparisons, have also been published to tie in with the launch of the ship and the exhibition.

Martyn Routledge, Maritime Quest's senior designer, says the stories of the people involved in Cunard's history, from the shipyard workers to those who worked onboard ships and the passengers who sailed on them, form one of the most important parts of the exhibition. ''This is the first time much of the imagery we have used will have been seen in public,'' she says. ''We have tried to tap in and show a more unusual side to the history of Cunard.

''One section includes people's onboard diaries from the 1860s right through to the 1990s. They cover all the different eras and show what people were thinking while they were travelling, and their experiences onboard. Another section is about the role of Cunard ships during wartime, and we also have things such as original menus dating back to the 1840s.

''We tried to include anything we thought might excite people. One of my favourites is the immigration section. It tells the story from a social history point of view, including the conditions people travelled in to try and reach the New World, and their expectations of what they would find when they got there.''

When the QM2 sets sail on Monday on its maiden voyage - from Southampton to Fort Lauderdale, Florida, en route to the Caribbean - it will forge a different channel from the grand ocean liners of the past, simply in the interests of economic survival. Whether it can recreate their magic remains to be seen. n

Stars Aboard and Queen Mary 2: Book of Comparisons are published by the Open Agency, priced (pounds) 10 each plus p&p. Call 020 7740 7000 or visit www.openthebook.com