A NORTH Sea ferry operator is celebrating a summer upsurge with car numbers on its Harwich to Hook of Holland route up by 7%.

Stena Line, which achieved the upturn against a backdrop of tough conditions for the industry, said overall passenger numbers were also up.

In the three months to September, when Stena Line celebrated its 50th anniversary, the privately-owned ferry company grew numbers of cars on its Harwich route by 7.1% and total passenger numbers by 0.8 per cent, compared to the same period in 2011.

Freight volumes also increased by 17%, measured in freight units, across its three routes, including from Harwich, over the January to September period.

The ferry operator, the largest in Europe, achieved the summer upsurge during a quarter where air passenger traffic from the UK to the Netherlands fell by 0.8%, according to Civil Aviation Authority figures.

Stena Line’s growth equated to 3,000 additional cars and an additional 2,000 passengers to the Netherlands.

The quarter’s strongest monthly growth came in September, the month of Stena Line’s anniversary celebrations. Buoyed by promotional activity, the operator carried 11,000 cars to Holland during the month - a 17.2% year-on-year increase - and 46,000 passengers in total, equating to an 11.4% year-on-year increase.

Stena Line has also seen year-on-year growth across the North Sea for the year to date.

During the first nine months of the year, numbers of cars on the Harwich-Hook of Holland route rose by 4.2% compared to the same period last year, and total passenger numbers climbed by 1.4%.

Lars Olsson, Stena Line’s general manager for travel on the North Sea, said: “We are doing well. We are breaking some of the industry trends.”

“The summer was challenging for the UK outbound travel in general, with the Olympic Games dampening demand. Market conditions have remained testing and so Stena Line’s ongoing North Sea growth has bucked industry trends and the promotional work we carried out around our 50th anniversary in September has helped boost this further.

“During the golden anniversary month we grew our car traffic more than any other month in 2012, so we hope that the positive impact will continue and will assist in our full-year targets.”

In 2010, Stena Line introduced two newly-built passenger-freight Superferries on the route, representing an investment of �375m.

Stena runs twice daily return crossings on its Harwich to Hook of Holland route as well as more than 30 daily crossings on its various routes to Ireland.