Cameron, whose Conservative Party is widely tipped to win general elections due by next June, made the comments when asked if he used the increasingly ubiquitous microblogging site.
"No I'm not. I'm not on Twitter. I think that politicans do have to think what we say, and I think the trouble with Twitter (is) the instantness of it - too many twits might make a twat," he told Absolute Radio.
A short time later he compounded the problem when talking about the public perception of politicians here, which has plummeted to a new low following a recent scandal over parliamentary expenses.
"The public are rightly, I think, pissed off - sorry I can't say that in the morning - angry with politicians," he said.
Even worse came in a podcast made by the radio interviewer, in which he recounted an exchange between Cameron and his female press adviser immediately after the show.
The presenter explained: "He (Cameron) said 'That seemed to go OK.' She (his press adviser) said 'Yeah, apart from the language.' He said 'Oh, yeah, pissed, sorry about that, I'm really sorry'."
"She said 'No, it was the twat.' He said 'That's not a swear word.' His press secretary went 'It is'."
Speaking later, Cameron voiced regret over the whole exchange.
"You always have to be careful what you say. If I've caused any offence I obviously regret that. I was doing a radio interview and I'm sure that people will understand that."
Cameron's Conservatives are beating Prime Minister Gordon Brown's Labour Party by 18 percentage points, according to the latest poll Wednesday, putting the Tories on 42 percent and Labour on 24 percent.
AFP
"Hi, this is Zuma. You know what to do. No, no... not the machine gun. Leave a message..."
Need the latest political news, features, interviews and profiles? Visit our dedicated page...