More than 500 viewers have called the BBC to complain about a joke about murdering prostitutes made by presenter Jeremy Clarkson on the motoring programme Top Gear, the publicly funded broadcaster said on Tuesday.

Clarkson, 48, was shown driving an articulated truck during Sunday's show, which attracted an audience of 7 million.

"This is a hard job and I'm not just saying this to win favour with lorry drivers, it's a hard job," he said.

"Change gear, change gear, change gear, check your mirrors, murder a prostitute, change gear, change gear, murder. That's a lot of effort in a day."

Top Gear is one of the BBC's most popular programmes and is known for its edgy humour and banter.

By Monday morning 188 viewers had complained, rising to 517 on Tuesday morning following media coverage of Clarkson's comments.

The protests come after the resignation last week of Radio 2 head Lesley Douglas over the broadcast of a lewd prank call to Fawlty Towers actor Andrew Sachs by chat show host Jonathan Ross and comedian Russell Brand.

A spokeswoman for the English Collective of Prostitutes (ECP) told BBC television that Clarkson's broadcast was worse than the Sachs stunt, which prompted more than 30,000 complaints following a campaign in the Daily Mail.

"It's making light of murder," said ECP spokeswoman Cari Mitchell. "It's an absolute disgrace -- he should lose his job. The people who allowed this programme to go out have to be called to account.

"I think it's a sacking offence to make light of murder of anybody, never mind prostitute women who are vulnerable and criminalised."

The BBC defended the broadcast, saying viewers would not have taken it seriously.

"The vast majority of Top Gear viewers have clear expectations of Jeremy Clarkson's long-established and frequently provocative on-screen persona," the broadcaster said in a statement.

"This particular reference was used to comically exaggerate and make ridiculous an unfair urban myth about the world of lorry driving, and was not intended to cause offence."

Lorry driver Peter Sutcliffe, the "Yorkshire Ripper", murdered 13 women, some of them prostitutes, between 1975 and 1980.

Steve Wright, who also worked as a lorry driver, killed five women prostitutes in Ipswich in 2006.