An ad in which TNT Post compared itself to Royal Mail has been banned for implying that it offered the same service and similar prices as its competitor.
The leaflet showed a photo of a man in a TNT uniform and said: "What does my postie look like? Like this - in a smart uniform which our posties wear at all times on duty. Like Royal Mail, all are CRB-checked and fully trained in how to keep mail safe and secure."
It added: "We operate under exactly the same rules and regs as Royal Mail - authorised by the Government to carry mail and watched over by Ofcom."
A regional press ad said every item was delivered "at a competitive price - not just within Manchester, but all over the UK".
Royal Mail complained that the ad was misleading because TNT was not required to deliver to every address in the UK on a next-day basis in the way Royal Mail was.
Royal Mail also complained that the ad suggested TNT delivered mail all over the UK itself and also that it implied the service provided by TNT was better than the service provided by Royal Mail.
TNT said the ad was intended to reassure consumers about the security of mail rather than frequency of delivery and where it did not have its own network, it subcontracted Royal Mail to deliver, enabling it to provide a service across the UK.
The Advertising Standards Authority (ASA) said the ad suggested that TNT was subject to the same service levels as Royal Mail in all aspects of its service, including the obligation to deliver to every UK address every day, which was not the case.
It also said the reference to mail being "delivered ... all over the UK" was misleading in the absence of qualifying information that explained that delivery to most areas in the UK could not be carried out by TNT.
And it found that information in the ad did not allow readers to identify for themselves how TNT was superior to Royal Mail in respect of how its prices compared to those offered by Royal Mail.
It ruled that the ads must not appear again in their current form, adding: "We told TNT Post UK to ensure future ads did not suggest that they were subject to the same service levels as Royal Mail, that they delivered mail themselves to all parts of the UK or that their prices were competitive in relation to those offered by Royal Mail unless they could substantiate that that was the case."
A TNT Post spokeswoman said: " Whilst we disagree with the findings, we will comply with the request for greater clarity in the future."