An on-duty Ryanair steward downed a small bottle of wine and drank whisky from the aircraft’s drinks trolley while the flight was in the air, a court has heard.

Sam Thompson, a 26-year-old from Hertfordshire, admitted at Chelmsford Magistrates’ Court on Monday to having performed an aviation function as a member of cabin crew while his ability to do so was impaired by alcohol.

Witnesses saw him drink Jack Daniels from the trolley before taking a small bottle of wine from his pocket and “necking the whole bottle”, the court was told.

Thompson, of Warrenfield Close in Cheshunt, was breath-tested by police at London’s Stansted Airport after the flight from Rzeszow in Poland landed on 18 May.

The test gave a reading of 50mcg of alcohol in 100ml of breath, before he gave a lower reading of 39mcg at Harlow police station.

Nishma Khan, prosecuting, said the legal limit is 9mcg of alcohol per 100ml of breath – lower than the legal limit for driving of 35mcg of alcohol per 100ml.

Police were called shortly after 6pm that day after a witness reported seeing a member of cabin crew drinking while working on a flight, Ms Khan said.

The witness first saw Thompson drink Jack Daniels, before they “proceeded to film the member of staff”, Ms Khan said, adding: “He was still on duty while the flight was in the air.”

He is due to be sentenced at the same court on 3 August and was told he might be jailed.

Thompson’s lawyer Michael Carroll said the defendant and alcohol are “not the best of friends”.

Ryanair said in May that the flight was being operated by its sister company, Lauda Europe, and representatives of the airline said that the employee filmed drinking by passengers had been fired.

Presiding magistrate, Kristien Chafer, ordered a pre-sentence report to be prepared on the defendant, exploring all sentencing options, including custody.

He bailed Thompson until his sentencing.

Additional reporting by PA