The UK TV ad for the RB brand, created by Havas Worldwide London, was based on an interview between Smillie and Dr Lisa Ackerley, who was described as an expert in household hygiene.
Ackerley showed a jug full of brown sludge and said: "This is the sort of stuff that can actually build up in part that you can’t see." She then revealed a further 15 jugs to demonstrate 15kg of dirt passed through a dishwasher over its lifetime.
The Advertising Standards Authority received one complaint about the ad, on the basis that it exaggerated the amount of dirt that would build up in a dishwasher if the cleaning product was not used.
The complaint, made in March, challenged whether the ad misleadingly implied that a dishwasher would be less effective at cleaning a load if the product was not used.
In its response to the ASA, RB said it had provided evidence to Clearcast that showed the volume of soil that typically passed through a dishwasher.
Prior to broadcast RB had given evidence to Clearcast to demonstrate the product’s efficacy and a study that, they believed, demonstrated the product’s cleaning capability.
But the ASA said it had not been given the full studies to back up the ad’s claims and noted that neither of the studies it had been sent measured the product’s performance when used in "real-world conditions".
In its ruling, published today, the regulator said: "Therefore, because we considered that viewers would interpret the ad to mean that a dishwasher would clean a load more effectively when a consumer used Finish dishwasher cleaner, as opposed to no cleaning product, and we had not seen sufficient evidence to confirm that this was the case, we concluded that the ad was misleading."