The advert, offering to refund losing bets if the South African Paralympian is found not guilty of the murder of his girlfriend Reeva Steenkamp, has become the most complained about UK advert ever.It showed a mock-up of an Oscar statuette with the face of Pistorius superimposed, with the claim: "It's Oscar Time. Money back if he walks. We will refund all losing bets on the Oscar Pistorius trial if he is found not guilty."A total of 5,525 complaints were received by the Advertising Standards Authority (ASA), which took the unusual step of ordering that the ad be immediately withdrawn while it investigated.The watchdog looked into complaints that the ad trivialised the issues surrounding a murder trial, the death of a woman and disability, and that it was likely to cause serious or widespread offence.Paddy Power said it was "unsurprising" that complaints had been received, given the high level of media coverage - but insisted it "strongly believed" that offering a market on a leading news story did not trivialise the issues in question.The bookmaker said the ad was a reflection of public interest and was not a commentary on death, violence or disability.While it accepted that there was a double meaning to "if he walks", it claimed it was an inoffensive and relevant play on words.We told Paddy Power to ensure their future ads did not cause serious or widespread offence and did not bring advertising into disrepute.Advertising Standards AuthorityAccording to The Sun on Sunday, which published the advert, it took the decision in good faith and regretted that offence had been caused.The newspaper said it would ensure the concerns were taken into account in future.But the ASA has ruled that the advert must not appear again in its current form, as it found it was likely to be interpreted as making light of the murder trial, a woman's death, and disability.The ASA acknowledged that the ad made no explicit reference to death or violence."We acknowledged that the ad had appeared in the context of a high profile murder trial that had received extensive media coverage and was of interest to the public," the watchdog said."We considered it would therefore have been reasonable to foresee that serious or widespread offence was likely to be caused by placing an ad that sought commercial advantage based on that trial and which made light of the sensitive issues involved."Given the content of the ad, and the prevailing circumstances at the time of its publication, we concluded that it brought advertising into disrepute."