A motorist with a medical condition which makes him appear to be over the drink-drive limit has lost a bid overturn his conviction.
Robert Woolfe, 53, of Harlow, Essex, suffers oesophageal reflux, causing him to regurgitate his stomach contents.
He was fined and disqualified after a positive breath test despite drinking only one pint of lager, a bottle of beer and two soft drinks.
Two High Court judges dismissed an appeal against conviction on Friday.
Mr Woolfe gave breath tests of 69mcg and 65mcg per 100ml of breath against a legal limit of 35mcg when stopped by police in October 2004.
Epping magistrates accepted he had drunk one pint of lager and a bottle of beer - which would normally amount to only 10mcg.
But he was convicted because the magistrates held they were bound by a previous case which allowed for no differentiation between deep lung breath and breath contaminated by alcoholic mouth contents.
The High Court judges also refused Mr Woolfe leave to appeal to the House of Lords, despite argument from his lawyers that the decision was an unjust and unfair result for someone who had drunk less than a third of the recommended maximum.
But they sent the case back to the magistrates for them to reconsider whether the medical condition, although it did not provide a defence, amounted to a "special reason" for not imposing a driving ban.
Lord Justice Maurice Kay said: "Breath specimens do not provide a precise calculation of how much alcohol a person has consumed.
"There are numerous variables, including age, size, gender, metabolic rate and so on."