It is a ceremony almost as old as time itself and tomorrow it will signal the next major stage in the construction of Southampton's latest luxury superliner, the 85,000 ton Arcadia.

This key development comes as the British cruise industry, with its main hub in Southampton docks, enjoys buoyant times with ship operators announcing that the number of UK passengers has passed one million for the first time.

The P&O Cruises' vessel, Arcadia, now taking shape in Italy, is due to enter the water for the first time when the ship is floated out from the building dock to a nearby fitting-out basin as work gathers pace on the construction programme.

Before that manoeuvre takes place the traditional mast stepping ceremony will take place on board the ship, set to enter service in Southampton in April, 2005, at the Fincantieri shipyard near Venice.

The origins of the ceremony, in which a coin is placed in the superstructure of the ship, are lost in the mists of time but it is thought the ancient Romans carried out a similar ritual as they believed the offering of money would ensure a safe future for the passengers and crew during the vessel's career.

According to the tradition, always observed by Carnival Corporation, the parent company of P&O Cruises, during the building of a new ship, the coin must be put beneath the mast before the first drop of water ever comes in contact with the vessel.

The ceremony also calls for the coin to be put in place by a female associated with the ship, so the newly minted sterling silver £1 coin will be positioned by Sabrina Dunkerley, one of the youngest cadets in the P&O Cruises' fleet, who will be joined by David Dingle, managing director of Carnival UK.

When construction first started the ship was initially ordered on behalf of P&O Cruises' sister company, Cunard and was destined to be called Queen Victoria.

Then in a major change of mind the Miami based Carnival Corporation decided that the vessel would be switched to P&O Cruises' Southampton based fleet and re-named Arcadia.

The largest cruise ship ever built exclusively for British passengers, Arcadia will feature more private balconies than any other UK-based vessel.

Of the 984 cabins on board Arcadia a total of 677 will have balconies while the most lavish of her 67 suites and mini-suites will feature whirlpools on the verandas.

Ship operators believe that the introduction of vessels such as Arcadia will continue to increase present interest in cruising which resulted in a 12 per cent rise in sales last year with passengers spending more than £1 billion of their ocean-going holidays.

A total of at least 210 separate cruise ship calls are booked with the port of Southampton during 2004 and early indications suggest that this figure will increase even further next year.