One might expect the Daily Star and Loaded magazine to fall for a hoax about takeaway food, but it was Radio 4's Today programme that got stung.

The show, well known for its upmarket breakfast audience and journalistic standards, devoted airtime to the former strongman Geoff Capes's campaign to highlight the "plight" of Britain's struggling fish and chip shops and pizza parlours.

Capes claimed high-street fast-food outlets were under threat from the march of new supermarket convenience food. The campaign's logo read "Geoff Capes says Support Your Local Takeaway" under a picture of the former policeman and champion shot-putter.

Thousands logged onto the website saveourtakeaways.com where they were offered the chance to enter a competition to win a year's supply of kebabs.

Today carried an interview with Capes, despite the unlikely premise of the "campaign", which flew in the face of the healthy growth of takeaway outlets. In reality, the "campaign" was a stunt by an advertising agency, McCann Erickson (motto: "Truth Well Told"), to promote a snack pot.

"We chose Geoff because it was obvious he liked his takeaways," said Rich Chant, a copywriter at the agency. "We wanted to find someone crap so we could make it look like a really amateurish campaign.

"But actually he's been really good," he added.

Today, which has repeatedly refused to dumb down, preferring to pursue a highbrow, intellectual agenda not always popular with BBC bosses, was left rueing its error.

A spokesman for the programme, whose presenters include John Humphrys and John Naughtie, said: "We apologise to our listeners for getting this one wrong."

The purpose of the "campaign" ­ the promotion of Snack Stop ­ will become apparent in a £4m advertising campaign beginning this weekend in which Capes will star.