Police first became concerned when they spotted a driver crawling along a busy Worthing road in a Ford Fiesta.

But they let it go because they were in a hurry to answer another call.

When they spotted the car still creeping along the road in Worthing as they made their return trip they decided to pull it over.

Drug user Mark Heatley, 25, of Cheshire Crescent, Tangmere, was fined £150 for possessing heroin when he appeared in court at Worthing.

Jonathan Wintle, prosecuting, told magistrates Heatley caught the officers' attention as he drove slowly along Dominion Road.

Mr Wintle said: "The driver seemed to want to pull over to the other side of the road but he was almost stopping."

Five minutes later, as the officers were on their way back, they spotted the same car, this time in Meredith Road.

A woman who had been a passenger was now driving and Heatley was in the passenger seat.

Mr Wintle said when the police officers pulled the car over Heatley's eyes were glazed, he was shivering and he appeared to be nervous.

They found a wrap of heroin on him and a blood test revealed he had taken morphine and cocaine.

Heatley, who admitted possession of heroin and four driving offences, was fined a total of £680.