Hawk-Eye's custodians have admitted the depiction of Phil Hughes' second-innings lbw dismissal in the Galle Test was rendered inaccurate by "a tracking mistake".

The visible discrepancy between Hawk-Eye's graphic and television replays led to the incident being referred to the ICC by the officiating umpires, under the governing body's conventions for the assessment of decisions made under the DRS.

Steve Carter, the managing director of Hawk-Eye Innovations, said the mistake had been the result of several factors, one of which was the fact the ball had travelled less than 40cm between pitching and striking Hughes' pad. Under Hawk-Eye's configuration for the Sri Lanka series, ball-tracking cannot be deemed conclusive if the distance between pitching and impact is less than 40cm.

"Yes, we made a tracking mistake, and the Hawk-Eye track didn't deviate enough off the wicket. We informed the ICC immediately after the game to make them aware that this was the case," Carter told ESPNcricinfo. "Despite the small distance from pitching to interception, and other mitigating circumstances that have been explained to the ICC, we should have done better. Lessons have been learnt from this instance and the probability of it happening again in the future is greatly reduced.

"Our track record as part of DRS is very good. This is our first error in a long time, and the ability of Hawk-Eye to reliably provide accurate and definitive decisions compares very favourably with other technologies and replay angles that are used to assist the umpire in different parts of the DRS protocol."

Hughes was given out lbw on the second evening when he attempted to sweep Tillakaratne Dilshan. Replays indicated that the delivery had spun appreciably from around middle stump towards off, but Hawk-Eye's prediction had the ball going straight on with the angle from round the wicket to strike leg stump. The decision was upheld not because of the errant Hawk-Eye tracking, but because the third umpire Tony Hill found insufficient evidence to reverse Richard Kettleborough's original call.

Carter said previous queries about Hawk-Eye's accuracy in the circumstances of the Hughes dismissal had led to the addition of a graphic to indicate that the point of impact was less than 40cm away from the point of pitching, meaning the onus for the decision would return to the on-field umpire's judgement. This graphic was not in place for Hughes' dismissal, however.

"There was less than 40cm of travel between the pitching point and the interception point," Carter said. "This has been an issue that has been raised in the past, and led to the implementation of the 40cm graphic. We are currently under instruction that the 40cm graphic shouldn't be displayed in the circumstances of the lbw appeal in question."

Daniel Brettig is an assistant editor at ESPNcricinfo