A blood sample taken from England cricketer Graeme Swann when he was allegedly drink-driving may have been contaminated, a court heard today.
The off-spinner's trial resumed today after his successful winter with the national team.
Swann was a key member of the side that won an Ashes series in Australia for the first time in 24 years.
He is in England's Cricket World Cup squad but has not travelled to Bangladesh as his wife is due to give birth.
He appeared at Nottingham Magistrates' Court today wearing a dark-coloured suit, shirt and tie.
The trial, which started in August but has faced several adjournments due to Swann's cricketing commitments, has heard he was stopped by officers on patrol in the West Bridgford area of Nottingham on April 2.
The court previously heard he had drunk three or four glasses of white wine earlier in the evening to celebrate his birthday.
When he returned to his £350,000 detached house in West Bridgford, he found one of his and wife Sarah's two cats - called Max and Paddy - stuck under the floorboards after builders had been working on their home.
Unable to find a screwdriver to undo the floorboards, Swann decided to drive his new white Porsche Cayenne to the nearest 24-hour Asda to buy a set of screwdrivers, the court heard.
His solicitor Phillip Lucas previously argued there was no case to answer on the grounds that of two samples of blood taken that night, it was the second that was analysed when the first was suitable for testing.
That second sample showed Swann's blood had 83mg of alcohol in 100ml of blood, which is over the legal limit of 80mg.
But in December District Judge Julia Newton decided the trial should go ahead.
Today defence expert Dr John Mundy, a forensic alcohol consultant who previously worked for the Metropolitan Police's laboratory, said the blood sample may have been contaminated.
He said sometimes samples could be contaminated by the rubber bungs used in the vials, which may have happened, especially if the nurse who took the sample, Lisa Hodgkinson, had "agitated" the blood by moving it up and down.
Dr Mundy said: "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 the contaminants could add to the alcohol reading, making it higher than it really was.
"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."
Asked by Mr Lucas, defending, if that could give an elevated result, he said: "That's correct."
The court previously heard that Ms Hodgkinson took a second sample of 8ml of blood from Swann as she feared her first sample of 2ml was not enough.
But today Dr Mundy said the first sample would have been adequate.
He said tests could be carried out on as little as 0.24ml of blood.
The court heard that samples are split into two for tests, but Dr Mundy said technically the first 2ml sample could have been used as 1ml was "ample".
He said: "I think this sample should have been sent to the laboratory.
"As the day-to-day head of the Metropolitan Police laboratory, if this had been done in the daytime, which this wasn't, obviously, an officer would have phoned me up and said 'Will this be OK?' and I would have said 'Yes'."
But under cross-examination from prosecutor Tara Kelly, Dr Mundy said the more blood that was taken, the better it would be as it would allow latitude for re-testing.
He said: "If I was pushed, I would recommend 4ml to be split into two bottles, that's 2ml per bottle.
"But obviously I am not suggesting that's the minimum amount suitable for analysis but the more you have, the easier it is for the sample to be split and it's easier for the analyst to have more blood there."