The reverse side said: "Discover our irresistible rates, faster service and ease of use when you make the switch to TNT Post - the UK's leading competitor to Royal Mail... See how much you could SAVE with this simple savings calculator chart."
The chart displayed savings per annum achieved when using the TNT service to post a stated number of items per day. Below the chart the text stated: "Prices are for TNT Post's PremierSort Flex service and compared to Royal Mail 1st Class."
In its complaint to the Advertising Standards Authority, Royal Mail argued that the comparison was misleading and unfair because it compared TNT's two- to three-day delivery service with its next-day service.
TNT Post said that the comparison was transparent, specific and was neither unfair nor misleading. It said its postal service competed with several different Royal Mail services and said that a comparison of its two- to three-day services with Royal Mail's first and second-class services was valid because it enabled customers to make an informed choice.
But the Advertising Standards Authority ruled that although TNT had included the disclaimer stating that prices were for its PremierSort Flexservice, many readers would be unaware that the service had a two- to three-day delivery period.
The ad watchdog also said that, because the ad included claims such as "Discover our irresistible rates, faster service... quick delivery", readers were likely to infer that the two services had similar delivery periods.
The ad was therefore deemed unfair and likely to mislead.
The ASA reviewed further comparisons between the two companies found on the insert about savings, delivery time and reliability and ruled they were likely to mislead because the exact context of the comparisons was not made clear, in relation to distinctions between Royal Mail's first- and second-class post.The cASA upheld the complaint and told TNT to ensure that the basis of any future comparisons was prominently stated in the body copy of the ad.