A motorist had almost four times the legal limit of alcohol in his breath when he drove the wrong way along the M4.
Lee Johnson, 44, was arrested after driving a red Citroen Berlingo van in the wrong direction along the westbound stretch of the motorway between junction 11 and 12 in Reading at around 11.30pm on Saturday, police said.
He was found to have 120 micrograms of alcohol per 100 millilitres of breath in his system.
Johnson, of Colman Road, London, pleaded guilty to dangerous driving, driving while over the alcohol limit and driving without insurance at Reading Magistrates' Court, Thames Valley Police said.
He is due to be sentenced in the New Year.
Senior investigating officer Gaz Doughty said: "Such behaviour on our roads has far-reaching effects, not just for the impaired driver but for any innocent road users affected by their destructive decisions."
