A man dialled 999 to complain to West Midlands Police about the quality of a prostitute in the West Midlands.
The man contacted officers saying the prostitute should have action taken against her for breaching the Sale of Goods Act for "making herself out to be better looking than she was".
Officers advised the man that public solicitation of sex was illegal and have now sent him a warning letter.
West Midlands Police spokesman Lee Page said: "We had a call on Tuesday at about 7.30pm. The caller said he had arranged to meet a prostitute outside a hotel and he did not like the look of her.
Click to listen to part of the call.
"He said she made herself out to be better than she was.
"When he took issue with this she took his car keys, ran out of the car and then threw them back at him."
Mr Page said the caller originally refused to give his name but inquiries had enabled officers to locate him.
The man has now been sent a letter. Officers have not revealed where the hotel where he met her was.
Solihull Police, who investigated the matter, took to Twitter to reveal details of the bizarre case.
Unbelievable… man just reported a ‘lady of the night’ for breaching Sale of Goods Act with her looks. Sergeant reshaping the man's attitude.— Solihull Police (@SolihullPolice) June 11, 2013
The act of prostitution is not in itself illegal, but various laws criminalise activities around it.
The 1956 Sexual Offences Act bans running a brothel and it is against the law to loiter or solicit sex on the street.
Adverts placed in phone boxes have been banned since 2001. There are also general laws on public nuisance and decency which can be used to target the sex trade.
The man's initial 999 call was terminated within a few minutes in order to free up the emergency line, with a follow up call then made to the man by Sgt Jerome Moran at Solihull police station.
During the second call, a recording of which has not been released, he told the officer that he wanted to report the woman for breaching the Sale of Goods Act.
Sgt Moran said: "It was unbelievable; he genuinely believed he had done nothing wrong and that the woman should have been investigated by police for misrepresentation.
"I told him that she'd not committed any offences and that it was his actions, in soliciting for sex, that were in fact illegal. Unhappy with the response, he then insisted on coming down to the police station to debate the matter.
"Although he refused to give me his details following our conversation, I was able to identify him and have since sent him a letter warning him about his actions.
"We recognise that prostitution often involves the exploitation of some very vulnerable members of the community and we will actively pursue those who seek to exploit that vulnerability."
Sgt Moran added: "We take around 1,500 999 calls each day and more than 90 per cent of those are answered within 10 seconds but each call often takes minutes to deal with, as staff have to clarify the situation. It might not sound like much but, if someone is trying to get through to report a genuine life or death emergency, then a minute is a very long time to wait.
"On this occasion the man in question was given a warning, but wasting police time is a serious offence and carries a maximum sentence of six months imprisonment next time he may not be so lucky."