The Advertising Standards Authority (ASA) has banned an advert for Vodafone broadband after it was ruled to be misleading.
The TV advert in question was part of a campaign starring Martin Freeman and featured the actor playing an online game, when he loses internet connection at a vital point.
After his friend tells him to "just get Vodafone", a voiceover explains that the provider would guarantee home broadband speeds, or offer a discount on their monthly bill until the issue is fixed. A radio advert followed a similar storyline, while the claim was also featured on the company's website.
The ASA deemed this to be misleading, as consumers could interpret the ads to mean that Vodafone was able to guarantee speeds fast enough to avoid issues such as buffering.
In fact, smaller text explained that Vodafone used a measure called 'sync speed' to determine connection quality. The ASA noted this refers to the maximum speed the router on any given connection was able to receive, but did not take into account other factors such as traffic on the line.
The ASA said: "We were concerned that any guarantee based on sync speeds, which were not an accurate measure of the speeds experienced by customers on their devices, was likely to result in some customers experiencing problems associated with slow speeds but still not qualifying for the guarantee."
Nine complaints were received by the regulator about the ad, including one from Vodafone's competitor BT.
In upholding the complaints, the ASA ruled the claims made in the ads were misleading, unsubstantiated and exaggerated, and must not be shown again in their current form.
A spokeswoman for Vodafone told the BBC the company was disappointed by the ruling and stated the ASA had "misunderstood" the offer.
She added that the guarantee "is still unmatched in the market, as no other major brand offers a promise like this across their entire range, nor do they apply discounts directly to customers' bills if they don't deliver".