Tullett Prebon, the interdealer broker led by City luminary Terry Smith, has been ordered to pay a rival firm nearly $1m in damages following a dispute over an alleged misuse of data, in the latest court case to strike the fiercely competitive industry.

Tullett Prebon was ordered to pay rival broker BGC Partners damages worth $0.8m over the misuse of market data it had been provided with by BGC, a regulatory filing said today. The ruling concerned an agreement over a jointly-created product to price swaps called "swapmarker 100" which included proprietary data from both firms.