With thousands of bedrooms in as many locations, it's easy to imagine that chain hotels all offer the same bland, basic experience. However a new survey by Which? reveals they may not be as homogenous as you think, with a huge difference in quality between the best and worst brands.

The survey of 36 UK hotel chains asked Which? members to rate the chains on cleanliness, customer service, bed comfort and value for money. The results are based on 8,267 hotel stays in the past year.

Topping the table is Q Hotels, with 21 four-star hotels, which received a full five-star rating for cleanliness and room fixtures and an overall customer score of 78%. One member described their stay as "excellent in every department".

For Britannia Hotels, however, the results tell a different story. The chain, described by members as "shabby" and "run down", scored a dismal 36% overall, to come bottom of the list. Some guests were shocked to find bedrooms without windows. One disappointed customer said: "It was £10 a night extra for a window in the room!"

Travelodge, the most visited chain in the survey, with 500 hotels, fared only slightly better, with an overall score of 50%. While it received a three-star rating when it came to value for money, its breakfasts were awarded just a single rather unappetising star.

The chain that should be most satisfied with the results is Premier Inn. The budget chain came third, in the company of luxury brands such as Radisson Blu Edwardian (second), Sofitel (fourth) and Double Tree by Hilton (fifth).

With 650 hotels in the UK, Premier Inn is also the biggest chain on the list. In a recent ad campaign for the hotel comedian Lenny Henry promises "a great night's sleep guaranteed". According to Which?, one in 10 members requested a refund under this promise. Members said refunds were offered "with no quibble", and sometimes even "without requesting it", presumably as soon as a complaint is made. The chain won a five-star rating for customer service.

Which? editor Richard Headland, said: "Our survey has revealed a king-sized bed gap between the best and worst hotel chains in the UK and shows you don't have to spend a fortune to get a decent overnight stay."

The top six hotels customer satisfaction score:

Q hotels 78%
Radisson Blu Edwardian 77%
Premier Inn 76%
Sofitel 74%
DoubleTree by Hilton 71%
Park Plaza 71%

And the bottom six:

Britannia Hotels 36%
Travelodge 50%
Ramada 51%
PH Hotels 51%
De Vere Village 51%
Shearings Hotels 52%