The CMA launched its investigation last week over concerns about the “accuracy and presentation of information on sites” which could stop holidaymakers from finding the best deal and potentially break consumer law.

Aito chairman Derek Moore said the association looked forward to the CMA conducting a “full investigation” of the behaviour of such sites, adding that Aito would be “submitting its members’ views on how [online sites’] big-company trading practices affect both SMEs and consumers.”

Moore added: “This investigation should, of course, have been instigated several years ago, before these online reservation sites had gained such a high level of control over the market. There seemingly isn’t a shack in the hotel world that is not featured by them.

“It is Aito’s strong belief that, with power and market dominance, should come a commensurate level of responsibility. Such responsibility is notably absent here, which is very disappointing.

“We at Aito urge the CMA to ensure that these super-large brands take stock of what they are doing and rethink their modus operandi, taking on board the importance of shouldering responsibility for their actions.

“Additionally, the sheer lack of transparency is worrying and does not serve well either the travelling public, the hotels featured on these sites or, indeed, the American companies’ UK-based competitors.”