MORE than 500 litres of chemicals spilled across the motorway just outside Worcester causing tailbacks of more than 13 miles.

Rush-hour traffic ground to a halt yesterday and police closed the stretch for almost seven hours.

Hydrogen peroxide, sodium hydroxide - caustic soda - nitric acid and neutraliser poured across the northbound carriageway just south of Junction 7 of the M5.

Crews from Worcester and Upton-upon-Severn, along with the environment protection unit from Evesham and incident support unit from Droitwich, were called to the scene to dilute the spillage.

The Environment Agency was also called.

Police closed the motorway at Junction 8 to avoid further tailbacks after the leak was reported at 4.45pm.

But it took nearly seven hours before the motorway was fully open around 11.30pm.

The flatbed lorry was carrying three containers of the chemicals, each containing 1,000 litres. One had a puncture near its base.

The chemicals are used in the photographic industry.

"It took forever to clear it all up," said Sub Officer Richard Jordan, of Worcester's Red Watch. "Although the chemicals were quite diluted they did still pose a threat.

"We had to plug the puncture and transfer the rest of the chemicals into another lorry.

"Luckily, what had spilled was going across the hard shoulder into the verge."

Traffic was held up for more than two hours, before one lane was opened at around 7.30pm.

"The opening of one lane eased the tailbacks," said Sgt Colin Middleton, of the Central Motorway Police. "Because no other traffic was being allowed past Junction 8 there was little build-up to the tailback that was already formed.

"There were cars joining from the services at Strensham but that was minimal.

"There was no risk to public health, though."