The ECB have requested clarification from the ICC on the chain of events that led to Jonathan Trott being adjudged lbw in England's second innings at Trent Bridge.

Andy Flower, the England team director, went to see the ICC match referee, Ranjan Madugalle, after the TV umpire, Marais Erasmus, overruled the on-field umpire, Aleem Dar, following Australia's review of Dar's decision to give Trott not out.

Erasmus took the decision to overrule Dar despite conflicting TV evidence and without the chance of inspecting Hot Spot from the crucial side-on position. Sky Sports, the host broadcaster who supply the Hot Spot cameras, told Erasmus the technology was not available as the delivery to Trott was not recorded because the technology had been cued to show the previous delivery, the dismissal of Joe Root to a catch down the leg side.

In a comment posted on ESPNcricinfo, Warren Brennan, Hot Spot's inventor, said the issue was down to "operator error".

"Here is the absolute truth from our perspective in regard to the Trott incident," he wrote, "it was operator error. My operator did not trigger the system in order to cater for the Trott delivery. Instead the operator sat on the Root delivery in order to offer a replay from the previous ball and did not realise until it was too late that he should have triggered the system for the Trott delivery as the priority. Simple mistake, something that anyone could have made but my Hot Spot operator has worked on the system since 2007 and to my knowledge this is the first serious mistake he has made."

England have asked the ICC to explain the protocol whereby a TV umpire can overrule despite an absence of the expected technological aides and asked for those protocols to be reviewed.

"It's very frustrating," James Anderson said afterwards. "Trott has hit the ball and been given not out. He did hit it. It is frustrating that it got overturned. We're all for technology because, since it came in, more decisions have been given out correctly than wrongly, so we want it."