With a budget airline owned by BA's parent company coming last in the short-haul league, the consumer watchdog said some customers reported felt BA was moving in the same direction.
Passengers cited the fact the airline, which is expected to face strike action by cabin crew next week, has even stopped giving out free food on flights of less than 5 hours, instead offering passengers a Marks & Spencer sandwich deal for £7.55.
Fares, however, did not appear to be dropping to match changes to the service, Which? said, making the airline seem bad value for money.
Meanwhile, Turkish Airlines, which serves more countries - 117 - than any other carrier, achieved top marks in two categories (food and drink and customer service) and four stars out of five in a further three (cabin environment, boarding and seat comfort). It scored 80 per cent overall, compared to BA's 67 per cent.
While BA still performed better than other UK carriers RyanAir and EasyJet, Which? said its scores had fallen significantly since last year.
“BA has a value for money rating of just two stars in this year’s survey, but last year it received three stars,” the report pointed out. “Additionally, in last year’s survey BA scored four out of five stars for food and drink, but it has scored just two stars this year.”
Propping up the table was Vueling, the Spanish low-cost carrier owned by International Airlines Group (IAG), BA’s parent company. It mustered a score of just 41 per cent, receiving one star for both food and drink and seat comfort and two stars in every other category. Iberia, another of IAG’s subsidiaries, also fared badly in the poll, scoring just 47 per cent.
Which? said: "Vueling’s former chief, Alex Cruz, last year became chief executive of BA; some passengers have told Which? they feel that BA is 'moving in the direction' of the budget airlines."
"One of Mr Cruz’s first major decisions was to scrap free food on BA flights of less than five hours. Instead, the airline now offers a £7.55 Marks & Spencer sandwich deal, which was met with controversy on social media."
The group said when they polled 1,500 members for their views, 81 per cent felt that ticket prices should be reduced as a result, but, so far, Which? said it had seen no sign of this happening.
The British carrier fared slightly better in the long-haul ratings, coming 10th place with a customer approval score of 60 per cent. Singapore Airlines, which came first, however, was far ahead with a 91 per cent customer rating.
Which? added: "Food on BA's long-haul flights is included in the ticket cost, but customers don't rate it highly - it got just two stars out of five. As recently as 2013, it received four stars in our survey. In 2014 and 2015 this was three stars. In January 2016 and in the latest survey it received just two stars."
Bottom of the long-haul pile was United. The airline, which last week faced criticism over plans to charge passengers extra to use overhead lockers, scored just 44 per cent — further suggesting customers resent being asked to pay for small things they believe should be included in the ticket cost.
A spokesperson for BA said: “We are always looking for ways to improve the premium service we offer to customers. On our short-haul routes we offer low fares for flights to major airport hubs with great departure times. Following customer feedback, from next year we will be providing high quality meal options from Marks and Spencer, a brand our customers know and trust.
”On our long-haul routes customers can check in online for free, deposit their bag in the hold for free and enjoy complimentary food and drink while watching our free in-flight entertainment.“
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