Mobile phone company O2 has been left with a six-figure bill for English National Opera's (ENO) cancelled performance in Trafalgar Square last week.
An industry insider said O2 had a 'play or pay' deal with the ENO for the event, which was transferred to the Coliseum at the last minute because of bad weather.
The source said this meant O2 was left with the costs of staging the event, while the ENO had no exposure.
An ENO spokesman said O2 had given the opera company "a significant amount of money to cover a variety of events", but he declined to confirm if O2 had paid the full costs for the 7 July event.
O2 said it had a sponsorship deal with the ENO, which included the Trafalgar Square event. A spokesman declined to comment on whether the company was exposed to any losses from the cancellation.
The ENO had been due to perform La Bohème at a free show in the square, which had been covered in artificial grass to create an atmosphere similar to that at Glyndebourne.