A blood sample taken from Graeme Swann shortly after his arrest on suspicion of drink-driving last year may have been contaminated, according to a forensic expert who gave evidence at the player's latest hearing at Nottingham Crown Court on Tuesday.

20722 - Swann's blood sample may have been contaminated

Swann, who is currently on paternity leave before linking up with his England team-mates ahead of their World Cup opener against Netherlands on February 22, was stopped near his home in West Bridgford shortly after 3.00am on April 2 last year, as he drove a white Porsche Cayenne towards a local supermarket, having arrived home to find his cat trapped under the floorboards.

During his original trial in August, Swann admitted to having drunk three or four glasses of white wine to celebrate his birthday, and was alleged to have told the arresting officer, PC Steven Denniss, he "shouldn't have probably been driving", when pulled over for driving a high-performance car in an area beset by a spate of recent burglaries.

The second of two blood samples showed that Swann had 83mg of alcohol in 100ml, which is over the legal limit of 80mg, although his solicitor argued that he had no case to answer, because it ought to have been the first that was used for testing. In December, however, district judge Julia Newton decided the trial should go ahead.

Dr John Mundy, a forensic alcohol consultant who previously worked for the Metropolitan Police's laboratory, told the court that the sample could have been contaminated by the rubber bungs used to plug the vials, making the reading appear higher than it actually was.

"If you get a bung that has contaminants - and they do have contaminants - I have seen quite bad contamination that can get into the blood and as such can interfere with the alcohol analysis one way or another," he said. "It means that it would add to the alcohol amount because you have a small area of contaminant adding to the large area of alcohol and that would cause the alcohol to go up."

Swann denies one charge of drink driving. The trial continues.