Boxer Joe Calzaghe was named the BBC's Sports Personality of the Year
The BBC's integrity was "compromised" when a soft drinks company sponsored the Sports Personality of the Year in 2007, the BBC Trust has ruled.
Editorial guidelines were breached by the deal with Britvic, whose Robinsons brand was mentioned during December's programme, the watchdog said.
"Tighter controls" were needed on such agreements in the future, it added.
The BBC said it would not renew the Sports Personality agreement or other sponsorship deals when they expired.
Some 6.9m BBC One viewers saw boxer Joe Calzaghe take the prize, with coverage also on BBC Radio 5 Live and online.
ITV and RadioCentre, which represents commercial radio broadcasters, both lodged complaints.
These were not upheld by BBC management so both companies appealed to the trust.
"UK audiences expect to receive BBC programmes that are free of advertising and wholly impartial," the trust said in a statement.
"Anything that creates an impression that a programme may be sponsored is wrong and contrary to the BBC's editorial guidelines."
The Sports Personality of the Year programme should not have a commercial backer once the current two-year deal with Britvic expired, it added.
And the trust stressed there was no wrongdoing on Britvic's part.
The BBC said in a statement: "In the context of today's findings, the management of the BBC has reviewed its sponsorship policy and has concluded that it should no longer accept sponsorship from commercial bodies for any on-air BBC event.
"This conclusion will be reflected in our revised guidelines which will be put to the BBC Trust in October for approval."
The BBC said it earned around £1.5m each year from deals including Sports Personality of the Year, Proms in the Park, the Radio 3 New Generation Artists Scheme and the BBC Four World Cinema Award.
Non-BBC events such as the Baftas would not be affected, it added.
An ITV spokesman said the broadcaster was "delighted" at the outcome.