A TV advert which asks viewers to 'spot the trans' at a horse race is being investigated.
The advert by UK and Ireland bookmaker Paddy Power shows women at the Cheltenham Festival - a prestigious horse race in England - and invites viewers to decide whether they are 'stallions' or 'mares'.
The Advertising Standards Authority (ASA) received around 500 complaints about the ad and have launched a formal investigation into whether the 30-second TV spot caused serious 'offence to transgender people and is seriously denigratory to women'.
The advert continues with the voiceover speculating on the gender of each person in shot, saying 'woman' or 'man'.
After one emerges from a men’s toilet, the voiceover says 'Dog. I mean, man', before concluding, 'Good luck with that.'
A spokesman for Paddy Power said the advert was intended to be a 'humorous interaction with customers'.
But trans activist Jane Fae didn't see the funny side, claiming that the advert is offensive, but that alone is not a good reason to pull it.
She told Gay Star News: 'What is a good reason is that the idea that a lot of drunk race goers should be trying to spot who is a trans woman is very likely to lead to abusive behaviour, violence or rape.
'And that applies not just to the trans community but probably all women.'
'While Paddy Power has a track record of piggy backing on offence as a way to boost publicity, in this instance they are not just playing with offence they are playing with real people.'
Sports channel ESPN has already pulled the advert but BSkyB and Channel 4 plan to continue airing it.
A spokesman for Channel 4 said the broadcaster always ensure adverts shown are compliant with the BCAP TV Advertising Standards Code, but say they 'believe it is up to our viewers to make their own judgment about the adverts they have seen.'
Fae says if the ad is pulled there is a danger of a backlash.
She said: 'The only way things can change is if somewhere in UK law, where a company deliberately incites violence as a means to gaining publicity is barred from certain industries.
'The only solution is not the ASA wrapping their knuckles and not withdrawing the ad, but something very radical.'
A Paddy Power spokesman told GSN the Lady's Day advert was preapproved by British television advertising watchdog Clearcast, who took the view that the humor, while not to everyone’s taste, fell short of causing offence.
The bookmakers have apologized for any offence caused, but have no plans to discontinue their advertising campaign.