* Protective coating diminishes bat marks, says BBG
* Former England captains critical of system
The inventors of cricket's 'Hotspot' technology have called for protective coverings to be removed from bats in order for the system to work properly.
The ongoing five-match Ashes series between England and Australia has been dogged by controversial umpiring decisions and there have been several occasions when Hotspot has failed to pick up edges.
Hotspot uses infrared cameras to determine whether the ball has struck the batsman, bat or pad, with any contact supposed to show up as a bright spot on the image.
"The type and thickness of the protective coating unquestionably affects the thermal signature of the Hotspot system," BBG Sports said in a news release on Saturday.
"In layman's terms the protective coating definitely diminishes Hotspot marks. BBG Sports believes that in order to achieve optimum Hotspot results then the removal of protective coating from bat edges needs to occur."
Former England captains Michael Vaughan and Alec Stewart described the statement as "embarrassing" and urged BBG Sports managing director Warren Brennan to go back to the drawing board with his system.
"I played in the 1980s, 1990s and early 2000s - bat tape and coatings have been around for 30 or 40 years so it's embarrassing for him to suggest it should be banned," Stewart told BBC radio.
"He has openly admitted there is a fault with his system. If you're a cricketer and you have a flaw in your technique you go back to the nets - I suggest he takes his technology back to the nets."
Vaughan doubted whether Hotspot could continue as an aid to test umpires.
"He is trying to protect his company," said Vaughan. "We just want technology that will present the right result more often than not.
"It shouldn't be down to the game of cricket to help Hotspot, it should be up to Hotspot to help the game of cricket. I don't think Hotspot can carry on as bat manufacturers aren't going to change ... it has to go."
England's leading batsman Kevin Pietersen was involved in an incident during the drawn third test in Manchester when he was given out caught behind, even though nothing appeared on the Hotspot review.
Earlier this week, Australia's Channel Nine TV alleged that silicone tape on the bats had confused Hotspot during the Ashes series and reported that the International Cricket Council (ICC) was investigating the matter.
The ICC, cricket's governing body, issued an immediate denial and said the report was "totally incorrect".
England captain Alastair Cook described the claims as a "blatant fabrication" and demanded an apology from the network.
Brennan acknowledged on Saturday that Hotspot was far from foolproof.
"At the end of the day no technology is 100 percent perfect, however at BBG Sports we are continuously researching and developing our products to provide the best technological service for sport," he said.