The BBC was plunged into a new deception row after a cameraman posed as a member of the public on one of its daytime shows.
The corporation - which was fined last year after a phone-in scandal - has suspended the production company behind the auction programme Sun, Sea and Bargain Spotting, hosted by Angela Rippon.
Contracts with Reef Television were suspended after an episode in which one of its cameramen, Craig Harman, falsely appeared as a member of the public to buy an "acrylic panel" from a contestant.
A BBC spokeswoman said the corporation was "extremely disappointed" the company had "misled the audience and us".
She added: "We take this matter seriously and have suspended all business with them, with their agreement, while we investigate. We regret that the production company has failed to meet the high standards the BBC expects of its programme makers."
A Reef Television spokesman said: "Reef Television wishes to apologise unreservedly for misleading Sun, Sea & Bargain Spotting viewers and the BBC.
"The company recognises it is a serious breach of editorial standards of which the BBC was not made aware. Reef Television will co-operate fully with the BBC's investigation and has launched its own inquiry."
The episode in question featured two people heading to Dinan in north-west France to find bargains and then selling them on a London market stall. Mr Harman has also worked on BBC consumer affairs show Don't Get Done, Get Dom.
The episode was first broadcast last July. The series - a key part of the BBC2 daytime schedule - has been pulled off the air and from the iPlayer web service.
The BBC instigated a major overhaul of programme-making methods after shows including Children In Need, Blue Peter and Comic Relief featured phone-ins where production staff pretended to be winners.
