Olympic organizers scrambled on Sunday to quell a backlash over depressing TV images of half-empty stands at the London Olympics as a government minister said an urgent inquiry had been launched to identify just who had failed to show up and why.

Sports fans from all over Britain who had been charmed by the Olympic publicity offensive but let down by a complex ballot system for the 8.8 million tickets, have been outraged by footage of empty seats at key venues including Wimbledon, one of the hottest tickets in world tennis.

Chairman Sebastian Coe, who threatened to name and shame sponsors that did not fill their seats, said missing spectators were mostly officials from international sports federations, other Olympic officials, their families and friends.

“It doesn’t obviously appear to be a sponsorship issue at the moment,” Coe said, after Culture Minister Jeremy Hunt said he thought the vacant seats had belonged to sponsors.

Coe, a former Olympic gold medalist on the track, said that only eight percent of allocated tickets went to big corporate sponsors such as Visa and Coca-Cola and that 75 percent of tickets were in the hands of the public.

– Reported by Karolos Grohmann and Paul Casciato of Reuters