Ryanair has been rated as the worst airline for the sixth consecutive year by Which?, with the consumer group claiming the Dublin-based carrier is still catching out passengers with hidden costs, reported the Guardian.

In the annual survey of short-haul airlines, passengers gave the airline the lowest possible rating for boarding, seat comfort, food and drink, and cabin environment.

According to Which?, Ryanair, which carries more passengers than any other airline in Europe, is also now the airline most consumers refuse to fly with; of those who expressed a preference, 70% said they would not use Ryanair.

Ryanair, however, dismissed the survey as “unrepresentative and worthless”.

The poll suggests Ryanair’s attempts to convince the flying public it is a better airline have yet to pay off, while the refusal to pay compensation to passengers affected by strikes has again left its reputation in tatters.

While Ryanair argues that repeated tweaks to its baggage rules have made travelling cheaper for many, the charges for assigned seating and cabin luggage can push their fares higher than those of rivals, Which? said.

The airline made £1.75bn last year from ancillary revenues, or extras, making up 28% of its total revenue.

Assigned seating on the airline can cost up to £40 per passenger for a return journey, while a wheeled cabin case costs an extra £12-£16 after changes were made to baggage rules last year. Charges for putting a small case in the hold have been reduced, but the cost of checking in a 20kg suitcase can more than double many advertised fares.

Of the mainstream airlines used most by Which? respondents, Jet2 fared the best. It was rated third overall, the behind Channel Island carrier Aurigny Air, and Swiss.

British Airways continued to struggle for approval, finishing 15th out of 19 carriers, while easyJet came 11th.

Wizz Air and BA’s sister airline Vueling shared a two-star rating for customer service with Ryanair.

Ryanair said price was the single most important factor for UK consumers choosing an airline. “The survey of almost 8,000 Which? members is totally unrepresentative and worthless compared to Ryanair’s 141 million customers.”

It added that “Ryanair is Europe’s No 1 airline with the lowest fares, with an average fare of just €39 [£35], a fraction of the high fares charged by Which?’s ‘recommended’ airlines.”