Last October, DFDS was seen to be promoting on its website a "duty free day trip – from £39 per car + four people" for travel by 15 December when booked by 31 October.

This was challenged by a complainant, who searched the DFDS website for trips from 26-30 October and was unable to find any fares at the advertised £39.

In response, DFDS said the £39 fare was available on all sailings on Mondays and Tuesdays between 6 September and 15 December. However, DFDS confirmed the price from Wednesday to Sunday was £55 with no £39 fare available on those days.

The firm also confirmed its usual text stating "date availability is subject to availability" had been omitted.

The Advertising Standards Authority found in favour of the complainant, stating it considered consumers would understand from the ad that there would be a "significant proportion" of fares available at £39 for the advertised travel window and would be "spread evenly across the travel period".

"The ad made no reference to the £39 fare being restricted to Mondays and Tuesdays and consumers would therefore have expected the £39 fare to have also been available on other days of the week," said the ASA. "We therefore expected any evidence substantiating the price claim would include all days of the week.

"However, we understood that while all sailings on a Monday and Tuesday during the travel period were £39, none were available at £39 on the other days of the week.

"We considered that because the £39 fare was only available on Mondays and Tuesdays, and that had not been made clear in the ad, the ‘from £39’ claim was likely to mislead."

DFDS has been told not to run the ad again in its current form, and to make clear in future where "from" pricing refers only to certain days of the week.