More than 60 viewers complained about a TV ad for Wonga.com, created by DTV Group, which showed a man having a dialogue with himself about how best to access a loan.
In the ad, a man stated that he needed to borrow £70, and ridicules the idea of going to a high street bank, with laughter heard in the background.
His ‘Wonga persona’ then assures him that he can receive the funds almost immediately, and that a £70 loan would cost £9.22 if repaid within five days.
Complainants claimed that the light-hearted presentation of the ad was likely to "mislead vulnerable viewers" about the nature and implications of the product, and also challenged whether the presentation of APR complied with the consumer credit regulations.
Wonga.com argued that the "average consumer was not vulnerable", and suggested the light-heartedness and laughter in the spot was aimed to tap into "customer dissatisfaction with banks".
However, the loans company admitted it had breached consumer credit regulations, as the typical ARP should have been displayed with greater prominence than the on-screen message "£70 for 5 days = £9.22. Total repayable £79.22".
The ASA upheld both complaints and the ad must not be show again in its current form.
An ASA spokesman said: "We considered that the tone of the ad, which included light hearted background music, colourful imagery, laughter related to the concept of obtaining a loan from a bank, a seemingly casual conversation and a character that wore a split costume and had half a beard gave the general impression that the service offered was a trivial one that could be considered in a light hearted manner.
"We considered the ad, in particular the statements "Wonga.com money made simple" and "Bet this is going to cost me an arm and a leg. No, you can keep those sir", references to the relatively small amounts available to borrow and the emphasis on the speed at which a loan could be obtained at all times of the day, was likely to be interpreted to mean that the solution to money problems was a simple one.
"Also, we considered the ad suggested that the decision to take the loan did not need to be carefully considered and was an everyday occurrence."