The new documentary, which was filmed onboard the 3,560-passenger Princess Regal as it sailed through northern Europe and Russia, is currently being shown on Thursdays at 8.30pm. It first aired on March 3, and has so far attracted a total of 3.6 million viewers.

The line said during this time, visits to its website had also risen by more than 40% year-on year, with new visitors to the website peaking at 66% year-on-year after the first episode aired.

Brochure requests have also more than doubled.

Tony Roberts, vice-president Princess Cruises UK, said: “We are thrilled with the success of The Cruise so far. An average of 3.6 million viewers have tuned in to watch it over the last three weeks, which is well above initial projections.

“With the number of people from the UK who went on a cruise last year recently confirmed at 1.8 million, the documentary is a fantastic opportunity to further raise the profile of cruising as a mainstream holiday option.

“From the feedback we have had off agents and our sister brands, we are confident that not only Princess but the whole of the industry is reaping the benefits of The Cruise.”