A woman who drove a luxury car at more than 100mph before crashing it into a young couple has admitted causing their deaths.

Mary Butres, an executive with a packaging firm, was one-and-a-half times over the drink-drive limit when the crash happened.

The 48-year-old lost control of a high-performance Jaguar XJ8 saloon when she hit standing water while returning from a day at the races.

She struck the Ford Fiesta of Mark Crompton, 20, and Jodie Brown, 19, which had broken down near the central reservation of the A1.

The helpless couple, who were walking away from their stranded car, were then themselves hit by the speeding Jaguar, a jury was told.

The impact was so powerful that they were hurled all the way on to the opposite carriageway and killed, Lincoln Crown Court heard.

Butres, of St Mary's Street, Stamford, admitted two charges of causing death by dangerous driving at Great Poynton, near Grantham.

Her passenger and business associate John Nichols, of Manor Road, Carlby, denies two similar charges arising out of the incident on May 12, 2007.

Christopher Donnellan QC, prosecuting, told the jury: "The driver was Mary Butres. Mr Nichols was in the front passenger seat, and it was his car."

He said Butres and Nichols, 58, had been at Nottingham races and were heading south when Butres lost control in an area of standing water.

Other motorists slowed to around 40mph, said Mr Donnellan, but Butres failed to alter her speed and continued to travel at "well over 100mph".

He said the speed – captured by the Jaguar's "black box" recorder, which activated at the point of impact – was "far too fast" for the road and conditions.

Judge John Milmo QC granted Butres bail to await sentence later and imposed an interim driving disqualification.

The trial of Nichols continues.