A 64-year-old man was spotted drinking half a bottle of wine in a Tesco car park before driving his vehicle.
Colin Jackman, from Bishopstone appeared before Aylesbury Magistrates on Monday.
The court heard how Jackman was spotted driving a Land Rover Defender before drinking the alcohol in Tesco Tring Road’s car park.
A witness alerted the police. Jackman was then seen to go into the store, and was observed by police officers at the checkout.
He then got back into the Land Rover and drove onto the petrol station forecourt, before eventually being apprehended in Aylesbury High Street.
Jackman, who has no previous convictions pleaded guilty to drink-driving.
In mitigation he said that he looks after elderly neighbours, doing their gardening and taking them to appointments, and that this would be affected by a driving ban.
He was banned from driving for 12 months, and must pay fines and charges of £554.
Jackman queried why when he was taken to Aylesbury Police Station he was not offered a blood or urine test.
He also challenged the accusation that he drank alcohol in the vehicle.
However magistrates Chris Morley, Peter Walton and Jane Creasey reminded him that the guilty plea meant that he had accepted the accusations in full.