Police have recovered 40,000 ecstasy tablets in their biggest ever haul of the drug.

The tablets - the most to be recovered in County Durham at once - were stored in four packages in the footwell of a four series Rover's passenger side, as it travelled on the A19 northbound on Tuesday night.

Eagle-eyed traffic officer PC Ian Ainsley, who was patrolling the road, spotted the parcels, one of which was open and had tablets spilling from it.

Thinking them suspicious, he stopped the car just north of the turnoff for Peterlee at around 7pm.

He discovered the tablets to be ecstasy with a street value of at least £400,000 and arrested the car's driver and sole occupant, a 47-year-old man from Ryhope, in Sunderland, on suspicion of conspiracy to supply a controlled drug.

The suspect is in custody at Peterlee Police Station, where officers continue to question him. The tablets have been sent to forensic science laboratories in Wetherby, West Yorkshire, where tests are being carried out to confirm them as ecstasy.

Detective Inspector Sue Knaggs, of Easington CID, said it was not unusual for traffic officers to make random checks when their suspicion was aroused.

"They have a wide range of skills and abilities and when they see something suspicious, they look at it," she said.

"It's just a normal type of thing that the officer would do. "That level of observation would be expected of all our officers."

DI Knaggs said the haul was a major victory in the force's battle against drugs.

"A number of recent operations have shown our determination to disrupt the drugs market in East Durham," she said.

"This was an excellent piece of police work by all those involved and has prevented a huge amount of ecstasy from coming onto the streets."

DI Knaggs said she believed that the drugs would have gone to a network of dealers to be distributed.

She denied that the problem of ecstasy was worse in East Durham than elsewhere.