Eight out of 10 UK hotel rooms are cheaper when booked directly by phone or email than through an online hotel booking site, Which? found.

The consumer group contacted 10 hotels and eight were able to offer a better deal than the one quoted by an online booking site. They offered either a better price or other incentives such as free breakfasts or upgrades.

The findings suggest travellers pay up to 12% more for their rooms using an online booking site.

Which? said prices are higher on online booking sites due to hotels paying commission for every booking made. This can be as high as 25% and is often passed onto the consumer in the price.

Booking.com and Expedia denied their commissions are driving up prices.

Booking sites also typically include ‘rate-parity clauses’ in their contracts with hotels, which prevent hotels from offering lower prices on their own websites than those listed on the online booking sites.

Rate-parity clauses have been banned in France, Italy and Austria for preventing competition. However, the Competition and Markets Authority (CMA) in the UK chose not to ban the clauses in its recent review of the hotel booking industry.

Rory Boland, editor of Which? Travel, said: “Customers shouldn’t be duped into thinking they’re getting the best price from a hotel booking site when more often than not, they can get a better deal by avoiding its commission and booking directly with the hotel.

“Hotel booking sites might be a good place to start your search, but you should always call or email the hotel for the best chance of getting the cheapest deal – even in cases where they can’t offer a better price, there’s a good chance they’ll throw in a freebie or two.”