Savvy travel bookers who click on low price adverts may find they are often lead to air, rail and bus websites which do not have any seats at the advertised reduced fares.

The advertising watchdog has found that in at least one case this is because there were never many low fare seats available at all, and has banned Megabus from advertising its seats as “from £1” after it was found only three per cent of seats were available at that price.

The company uses distinctive blue and yellow buses, emblazoned with the advertisement: “From £1 + 50p booking fee (subject to availability)”

However, the ASA has instructed the company not to use this tagline unless a significant number of seats were being sold at that price.

Two complainants flagged the misleading advertisement to the ASA, after Megabus sold its journeys from Aberystwyth to Birmingham as “from £1”, as well as its travel from Leeds to new destinations in Yorkshire and offered “day trips from £1” from London to Bath. The company assured potential customers that “as always, our fares are from £1”.