The payday loan firm Wonga has been banned from using a TV advert that failed to tell consumers of its 5,853% annual interest rate.

The company, which recently announced that it would be writing off the loans of 330,000 customers who would not pass new affordability checks it has had to introduce, advertised its short-term loans using an animation of an elderly woman talking to an anxious-looking man jotting down figures on a napkin. In the advert, the woman told the man: “You appear to be in a financial quandary, young fellow. At Wonga you choose exactly how much to borrow and for how long,” adding “you can even pay back early and save money”. The web address “wonga.com” was on screen throughout the ad, and was displayed prominently as it ended.

The Advertising Standards Authority said the promotion breached its code because the claim that customers would save money was likely to be interpreted as a statement that Wonga’s loans were cheaper than those from other lenders. It said that because this indicated price comparison, the lender should have disclosed it representative annual interest rate (RAPR).

The investigation was triggered by a complaint from Citizens Advice, which suggested that the advert was harmful and irresponsible because the phrase “you appear to be in a financial quandary” implied that a payday loan could be obtained for non-essential purposes; and that the claim “you can even pay back early and save money” was an incentive likely to trigger the code’s requirement to disclose the RAPR.

The ASA rejected the first complaint, accepting Wonga’s argument that the man was compiling a list of essential car parts while the voiceover referred to maintenance, and that advertising a loan that could cover making a vehicle roadworthy was not suggesting people borrowed on a whim.

In April, Wonga had another advert banned after complaints that it suggested its high annual interest rate was irrelevant. It has not screened any TV ads since the first half of the year and has ditched the puppets that used to be a feature of its marketing.