The ad showed the twin singers sitting by a swimming pool and discussing the cost of their holiday with comedian Omid Djalili. One of the twins says he found his holiday for £200 cheaper than his brother at travelsupermarket.

The ad carries the jingle “Save super amounts of money at travelsupermarket.”

Travel agents and members of the public complained that the ad exaggerated the typical amount that consumer might save booking through the comparison site and misleadingly implied that would always be cheaper that booking direct with a travel agent.

Travelsupermarket said that it had researched prices of five identical holiday packages in brochures of major travel agents “largely representative” of the sector at customers could save between £204 and £400 on a like-for-like basis, so the ad was based on “reasonable fact”.

The company, owned by, also disagreed that the ad made any representation that it would always be cheaper than booking directly with a travel agent.

The Advertising Standards Authority says that it had concerns regarding the robustness of the company’s research given the small sample used for comparison.

The ASA also noted that travelsupermarket was comparing its prices with brochure prices rather than with travel agents’ online prices, which were more likely to reflect up-to-date pricing.

It said that without further information, such as the date when pricing was examined, it could not determine whether the comparisons were fairly made and said it should not be repeated in its current form.

The ASA did clear the company of stating that it would always be cheaper than a travel agent.