A TV advert that implied British Gas would attend same day call-outs, even over Christmas, has been banned by the Advertising Standards Authority (ASA).
The advert, about a broken boiler, had a voiceover which said: "You can reach us every day. Even over Christmas."
The ASA, which received 11 complaints, said the advert was "likely to mislead" viewers over the service offered.
British Gas had disputed complaints, saying it wanted to show it would deal with all queries, even at Christmas.
The animated advert showed a house on a spinning planet before the voiceover reported that the boiler had stopped working.
A British Gas van appeared and a man walked from it into the house, while the voiceover saying: "Sometimes you need a little help there", adding: "Which is why you can reach us every day. Even over Christmas," and "Look after your world this Christmas with British Gas."
The company said it had not been its intention to advertise the speed of its response.
It believed a high level of service had been achieved despite adverse weather conditions during the festive period, which affected their ability to respond to same-day and next-day call-out requests at the level expected.
Those who complained said the advert implied British Gas would attend call-out quickly, particularly during Christmas.
The ASA upheld the complaints, noting that the advert gave the "overall impression" that customers could expect an engineer to attend on the same day that a problem was reported.
"Because this level of performance could not always be achieved, the ad was likely to mislead," it said.