Police today said it was only through 'sheer luck' that there was not a serious collision when Michelle Charlesworth got behind the wheel.
Officers stopped her Mercedes Benz on the A64 near Flaxton in Ryedale after it was seen being driven erratically on the evening of February 17.
When they asked Charlesworth to complete a roadside breath test, she gave a reading 158mg of alcohol per 100ml of breath – the equivalent of four-and-a-half times the legal limit.
She was arrested and taken into custody, where she returned a further reading of 167mg of alcohol per 100ml of breath.
Charlesworth, 49, of Ingramgate, Thirsk, pleaded guilty to drink driving when she appeared at Scarborough Magistrates’ Court on Tuesday
She was jailed for 18 weeks, banned from driving for three years from the date of her release and ordered to pay a victim surcharge of Â£115.
Speaking about the sentence, Traffic Constable Jamie Lord said: “The reading of 167mg that Charlesworth returned that night is completely shocking.
"How anyone can get behind a wheel with that amount of alcohol in their system beggars belief."
The roads policing officer said Charlesworth not only consumed a large amount of alcohol that evening and got behind the wheel, she also drove erractically along one of the busiest A roads in the region.
"It is only through sheer luck and the quick thinking of the member of the public who witnessed her driving and alerted us, that a serious collision was avoided," he said.
“I hope the sentence handed to Charlesworth serves as a stark warning to those who think that they won’t get caught or that they will only face a slap on the wrist and a fine – a prison sentence is a very real possibility, as this case clearly demonstrates.”