Drug addict Dennis Rollinson told a jury he was a drug user but not a dealer.
Rollinson told Bristol Crown Court he was aware of a close community of drug users in Weston-super-Mare.
Though an undercover policeman called "Ricky" showed the court covert footage of a man supplying him with two wraps of cocaine, Rollinson said it wasn't him.
He told the court: "I was in an alleyway buying drugs from the same guy that your undercover cop did."
Rollinson, 38, of All Saints Road in Weston-super-Mare, denies supplying a Class A drug in September last year.
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Speaking behind screens, the officer told the court he was using recording devices when he contacted a telephone number he had obtained and said he wanted to order drugs.
He told the court he was directed to the Montpelier area of the seaside town.
Ricky told the jury: "I recognized that as an area frequented by Class A drug users.
"When I arrived I recognized three people who were Class A drug users."
The undercover officer said he then made a third telephone call and ordered two street deals of crack cocaine.
Shortly afterwards a man arrived and Ricky handed him a £10 note and a £5 note in exchange for two wraps of crack cocaine.
The jury watched covert camera footage the officer captured of a man who sold him the drugs.
Rollinson was adamant he was no drug dealer.
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He told the jury: "It was just another day in a long list of days.
"The question is do I sell drugs?
"No, I don't sell drugs.
"The question is did I sell drugs on that day?
"No, I didn't.
"The covert officer has got it wrong."
The jury of seven women and five men is considering its verdict.
The case continues.
