Tickets for the maiden voyage of ''the longest, widest, tallest, most expensive cruise ship'' ever built have gone on sale.

Cunard's spectacular new flagship, Queen Mary 2, sails out of Southampton on January 12, 2004 for a 14-night crossing to Fort Lauderdale in Florida.

At 150,000 tonnes, the QM2 will be nearly ten per cent heavier than her nearest rivals, the Voyager series of Royal Caribbean. Her owner, the US cruise giant Carnival, which bought Cunard in 1998, faces a construction bill of £540m before the first passenger walks up the gangway.

The maiden voyage of QM2 looks like a major event to compare with the despatch of the Titanic. Interest is so intense that Cunard denies any current plans for an advertising campaign. Instead, it has circulated just 1,000 copies of the inaugural brochure to specialist travel agents - and notified 3,500 names on the waiting list.

Discounted for early bookings, fares for the maiden voyage start at £2,100. Grandest duplexes cost nearly £27,000 per person, but those travelling as third and fourth guests - usually family members sharing cheaper cabins and sleeping on sofas converted into beds - pay from £1,309.

Apart from the obvious historical connections with the first Queen Mary, the famous cruise ship and Second World War troop carrier, Cunard will ''sell'' QM2 by relatively low passenger numbers for such a huge vessel.

QM2 has a maximum capacity of just 2,500 passengers - giving each one living space on board of just over 57 sq ft, way ahead of most five-star US rivals.

The ship, the length of three and a half football pitches at 1,130ft, boasts such impressive technology that she will operate in port without towage. She will have 14 bars, ten restaurants, a 20,000 sq ft spa and 14 decks open to passengers. Duplex suites on two levels, the largest afloat, have walls of glass two floors high, and the ship will carry the world's only ocean-going planetarium.

QM2 is set to replace the QE2 on the Atlantic run - with crossings and return flight from £999. The QE2 will revert to a cruise programme based on year-round departures from Southampton.

About 70 per cent of first-year bookings on QM2 are expected to be made by Americans determined, reckons Carnival, to sample ''the biggest and the best''.

* Cunard reservations: 0800 052 3840.