Match referee Alan Hurst said the ICC's technology trial is far from perfect after the third day of the Bridgetown Test.

West Indies were left incensed after Shivnarine Chanderpaul and Brendan Nash succumbed leg before wicket to deliveries which appeared to be going over the top of the stumps.

Both decisions were arrived at by the on-field umpires Aleem Dar and Russell Tiffin after their decisions were challenged by the players, and television official Daryl Harper's advice was sought.

Windies could have been in a better position

West Indies closed on 398 for five, just three runs short of avoiding the follow-on, but they would have been in a stronger position but for their ill fortune.

"This is a trial system and some days you get good decisions and today we got two or three controversial ones," admitted Hurst. "We have got to wear them and learn from them."

Dyson visited Hurst while play was on

Nash's dismissal, after Dar initially turned down Graeme Swann's appeal, resulted in West Indies coach John Dyson and team manager Omar Khan visiting Hurst while play continued.

If he was incensed at the time, Dyson later calmed down, although he did question the merits of the system, which allows each team two challenges to umpiring decisions, which are maintained unless a challenge fails.

"One of the great things about cricket is it teaches you to accept decisions and get on with the game," Dyson said.

"I just went down the steps to have a chat with Alan Hurst. I wanted to clarify a few things. I think we are still getting to grips with the whole concept.

"When you play your whole life with the umpires being in sole charge but now sometimes find yourself in situations where you can question the decisions, it is hard to deal with," Dyson added.

"We were led to believe it was to eliminate the bad ones [umpiring mistakes]. But what we are seeing is all sorts of tactical decisions (to refer) are coming in."

England off-spinner Swann, who claimed three of the four wickets to fall on the third day despite suffering pain in his right elbow, claimed he was unaware of the ill feeling from the home side until after play.

The tourists felt hard done by in their first Test thrashing at Sabina Park when Ramnaresh Sarwan was reprieved in single figures after initially being given out on the field.

He has not looked back since, converting his score there into a hundred and following with two more, the latest an unbeaten 184 here.

"We didn't realise there was any controversy until we walked off the pitch," said Swann. "As far as we are concerned we got given a couple of leg-befores and they are five down.

England were the sufferers in Jamaica

"We felt aggrieved in Jamaica by a couple of decisions and West Indies feel aggrieved today.

"Obviously the system is not ideal if people are aggrieved with it but personally I have got no problem if they are going my way."

Sarwan, meanwhile, disapproves of the current model applied at Test level and would prefer the traditional mode of umpiring.

"At the end of the day we all make mistakes and I am a strong believer in things turning out even in the end," he said. "It also takes up too much time on the field."