The barrister at the prestigious 2 Hare Court chambers and a Recorder sitting at Croydon and Inner London crown courts for the last 20 years had 137 micrograms of alcohol in his breath, when the legal limit is 35.
He was tried and convicted in his absence of drink-driving, and did not turn up for a sentencing hearing last month.
Dawson was spared jail at Westminster magistrates court on Friday after Deputy Chief Magistrate Tan Ikram accepted he has Wernicke’s syndrome – a neurological condition which means he does not know he has drunk alcohol.
The court heard the other driver in the crash took the keys to the Mini Cooper from Dawson, who was arrested after he returned from walking his dog.
“Someone cynical might find that difficult to accept”, said the judge, referring to the barrister’s medical condition, “but I am referred to all the surrounding circumstances, including your own behaviour on the day.
“You thought you were walking your dog in the morning when in fact you were walking your dog in the evening.”
Dawson’s legal representative and Chambers colleague, Christopher Foulkes, told the court medical reports indicated “cognitive impairment and chronic memory impairment”.
“Mr Dawson would never have contemplated committing any such offence had he not suffered from that impairment. It is because of that impairment he did not contemplate it at all,” he said.
The head of chambers at 2 Hare Court, Jonathan Laidlaw QC, gave evidence for his friend and colleague of around 35 years, saying Dawson is stepping down as a judge and will not work again as a barrister.
“Professionally, he observed the highest of standards. He is old-fashioned in terms of his approach,” he said.
“It is horrifying to hear what has happened to him in recent months, and the idea he was driving a car with a breath at this sort of level, with all of the risk factors it presents to him and others, is extraordinary to me.
“I am not suggesting he wasn’t an enthusiastic socialiser – we all were – but James would never have driven drunk.”
Judge Ikram sentenced Dawson to a four-month community order, including an 8pm to 6am curfew, banned him from driving for three years, and ordered him to pay £870 in court costs and fees.
“I have to say that, in a case such as this, I would ordinarily not hesitate to send the driver of a vehicle straight to prison,” he said.
“I have accepted you have this disorder; I wish you well because it needs to be dealt with.”
Dawson, who was said to be at his Catford home “drunk” when he missed his earlier sentencing hearing in November, was convicted of drink driving.