REVILED by many but loved by others, Adelaide shock jock Bob Francis has decided to hang up the headphones.

After 57 years in the industry, the man with the motormouth says he will retire from FIVEaa at the end of the year, and insists he hasn't been pushed due to struggling ratings.

"I just decided I wasn't really enjoying coming into work each day any more," the 74-year-old evening talkback host said yesterday.

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"I talked it over with my wife (Anna Von Berg) and we thought it was the right time."

Industry insiders have speculated that Francis may have been pushed following a steady drop in ratings since the end of last year, which has seen his main rival, ABC 891 and Sunday Mail columnist Peter Goers, hitting No. 1 in the 7pm to midnight timeslot. However, Francis insists the choice was entirely his.

The Sunday Mail had arranged to meet Francis for an interview yesterday but station management intervened, preventing Francis from speaking any further or having his photograph taken.

GALLERY: Bob's amazing career

FIVEaa's general manager, Sean O'Brien, who this week announced he was leaving the station for a position at Channel 9, refused to comment on Francis's departure.

Francis, who made his radio debut on 5DN in 1957, is renowned for his attacks on dole bludgers, asylum seekers, welfare cheats - and basically anyone he doesn't agree with. He often branded combative callers d...kbrains and w...kers.

One of more memorable incidents was a six-minute on-air clash with a grandmother known as Sylvia, who rang to complain about his bad language, but was met with a barrage of put-downs from Francis. His mouth almost landed him in prison for contempt of court, when in a 2009 tirade he threatened on-air to "smash in the face" of Magistrate Gary Gumpl for granting a convicted sex offender bail.

MORE: The life and times of shock jock Bob Francis

And, in April, he was ordered to make an on-air apology for saying he hoped asylum seekers would drown.

Francis was inducted into the Commercial Radio Hall of Fame and received an Order of Australia medal for his services to charity.

MORE: Bob brings in the ratings

Outspoken independent Senator Nick Xenophon said Francis was a unique character.

"Love him or hate him, they don't make characters like Bob Francis any more," he said.

"I disagree with a number of things that Bob said but that's part of living in a democracy.

"I reckon people will look back on his career with fondness."

In an interview with the Sunday Mail last year, launching his book Kiss My Arse, Francis said his proudest moment was helping lure The Beatles to Adelaide in 1964.

MORE: Franics breaches radio decency code

"It was my 15 minutes of fame - but what a 15 minutes it was," he said.

"It just went on and on and on and on. They were just fabulous guys, no bulls...t about them, no great demands, and the four of them would be just sitting around talking, joking and just waiting to go on."

matt.gilbertson@news.com.au