If you did need another reason to use a reputable travel management company such as Simplexity Travel, then the latest findings by Britain’s competition watchdog could be it.

From 1st September, six hotel booking sites including Expedia, Booking.com and Hotels.com will be forced to make major changes after The Competition and Markets Authority found they routinely presented a false impression of a hotel’s popularity, engaged in pressure selling, misled consumers over prices and gave preferential treatment to hotels that paid the most commission.

The CMA said the pressure tactics and misleading discount claims used by the firms – which also include Trivago, ebookers and Agoda – could not only prevent customers finding the best deals, but could amount to breaches of consumer law.

Andrew Tyrie, the chairman of the regulator, said: “The CMA has taken enforcement action to bring to an end misleading sales tactics, hidden charges and other practices in the online hotel booking market. These have been wholly unacceptable.

“Six websites have already given firm undertakings not to engage in these practices. They are some of the largest hotel booking sites. The CMA will now do whatever it can to ensure that the rest of the sector meets the same standards.”

Booking sites will now be required to make it clear how hotels are ranked – for example telling people when search results have been affected by the amount of commission a hotel pays the site – and include the total amount due in the headline price, rather than adding additional costs at the end of the booking process. They have also agreed not to give a false impression of the availability or popularity of a hotel which might force customers into making a booking decision.

Not all firms were guilty of every misdemeanour, but all have agreed to abide by the principles set out by the CMA.