There are around 300 court convictions for drink-driving every day in Britain. Despite ever-growing public abhorrence of this most antisocial crime, numbers of drivers caught over the limit are rising.

You might think that the case against them was crystal clear, but according to Nick Freeman, a Manchester-based criminal lawyer and the first port of call for celebrities facing driving charges of all sorts, the reality is far more complex.

Take a few examples: Freeman successfully defended snooker star Ronnie O’Sullivan from the charge of failing to supply a urine sample, arguing that his depression made him “too stressed” to perform. He also represented the former EastEnders star Steve McFadden, who was convicted but whose ban was for a relatively lenient 18 months despite his being 2½ times over the limit.

Freeman told the court that McFadden “had a remarkable capacity for drink” and did not feel drunk. As part of its case, the defence got a police surgeon to examine McFadden as he downed the equivalent of nine double vodkas. “They concluded that at that level Mr McFadden, quite surprisingly, would not have felt intoxicated. He appeared for all intents and purposes to be quite sober.” Magistrates were also told McFadden travelled widely as part of his charity work.

Freeman attributes his success to meticulous preparation, knowledge of the law in detail and the old-fashioned art of advocacy. It also helps to come up with novel defences. “I was able to use the defence of automatism — being in a state of subconsciousness — for one driver who had been stopped by police and found to be three times over the limit. I argued successfully that he had been given a drink spiked with a date-rape drug,” he explains. Warrington magistrates accepted Freeman’s argument that the driver, Colin Quilty, had been given Rohypnol unwittingly.

Another success involved invoking a clause on coercion from the 1925 Criminal Justice Act to help clear a former model from a drink-drive charge. The woman, Ashley Fitton, had been stopped and breathalysed after an evening out with her husband. “I used the old piece of legislation to back up the argument that her husband coerced her into driving and that she was terrified she would be hurt if she refused.”

Drink-drive campaigners are obviously appalled at any suggestion that legal fancy footwork is used to escape penalties. “Some of the things these lawyers come out with are ridiculous,” says Mike Jobbins, chairman of the Campaign Against Drinking and Driving. “In a drink driving case there simply are no mitigating circumstances.”

Freeman says he too is surprised there are so many holes in the law. “From a moral standpoint, I’m amazed,” he says. “Why doesn’t the government say you’re over the limit and that’s that?”

But Freeman isn’t alone in employing unusual arguments to secure an acquittal. Nigel Ley, a barrister and author of Drink Driving Law and Practice, reveals the story of a man who had invented a self-sealing balloon and had worked all night to get it ready for a demonstration the next day.

“The solvents he used contained alcohol, and he blew a positive breath test when stopped by police driving the following morning. We won for ‘special reasons’, as the driver had breathed in the alcohol and not consumed any,” he says.

“A very few people have autobrewery syndrome, so that if they eat bread or something with yeast it will produce alcohol. However, the offence is having consumed too much alcohol, and alcohol you manufacture is not consumed.”

So just how successful is Freeman and the army of fellow lawyers taking on such controversial cases? Understandably, Freeman won’t reveal his acquittal rate but says he successfully defends drivers every week. “I represented two drink-drivers this week and both walked free from court,” he says. “I will look at any set of papers and see if there’s a defence. Every case I take on is my personal recommendation and I don’t lose very often. It’s very rare that I can’t find a way around a drink-driving case, whether that’s procedural, a defect in law or a factual difficulty.”

Freeman travels the length and breadth of the country, acting in trials on an almost daily basis, which in itself is extremely rare for a criminal lawyer. While it’s always a challenge, he says there are many arguments to find, and many procedural points that are missed.

However, even Freeman does not always win. Two years ago he argued that procedural irregularities at Wilmslow police station meant that his client, the Republic of Ireland footballer Mark Kennedy, should be acquitted of failing to supply a breath specimen. The magistrates rejected the claim and Kennedy was banned for three years.

Some defences, however, border on the comical. Close to the top of the list must be Steve Hearn, who escaped a drink-driving charge after Warwick crown court found he had been sleep-driving when he crashed his BMW after drinking four pints of lager. A blood test revealed he was 1½ times over the limit, but the prosecution dropped the charges after Hearn, who has a long history of sleepwalking, presented medical evidence to show that he could have been asleep when he drove the car.

Then there is the trombone player who, although stinking of alcohol, blew a negative reading by utilising his musical talents to fill the machine not with deep lung air but with air freshly breathed in through his nose.

Less fortunate cases are the man in Oldham who said he had eaten risotto made with what he had been told was chicken stock but had in fact been vodka, the man who claimed that having only one leg made his blood volume incompatible with the measuring capabilities of the breath-test machine and the man who said he had eaten too many chocolate cherry liqueurs. All were convicted.