The port of Southampton has received a royal pat on the back for its continuing commercial success.

The expansion of trade within the port, now one of the fastest growing in Europe, impressed the Princess Royal while she was in the docks with her daughter Zara Phillips for a unique twin cruise ship naming ceremony.

"In recent years, every time I have visited the port of Southampton it always strikes me how busy the place is and how the docks' business seems to be expanding,'' the Princess told guests at the ceremony.

"There always so much going on, so many ships in port and improvements being made all the time. It really is wonderful to see.''

The Princess Royal and her daughter, Zara were taking part in the first double cruise ship-naming ceremony ever to take place in the UK.

P&O Cruises' latest Southampton superliners Adonia and Oceana have now joined the company's already well established vessels, Oriana and Aurora, in a wide-ranging summer cruise programme.

The arrival in Southampton of the two identical P&O Cruises ships underlines the company's confidence in the continuing growth of Britain's cruise market, which has its main hub in the city's port.

Exclusively catering for British holidaymakers, Adonia and Oceana, already dubbed Southampton's White Sisters, represents a 22 per cent increase in the operator's overall passenger capacity, reflecting the belief that the appeal of cruising will continue to broaden.

More than 822,000 Britons took an ocean cruise last year, according to the Passenger Shipping Association, the UK trade body for the industry, which is a growth rate of six per cent, the highest increase since 1999.