Drivers are being urged to avoid the M4 in West Berkshire after a major incident between the Membury services and Chieveley.

A tanker carrying a cargo of caustic soda (sodium hydroxide) overturned at just after 10.15am today, spilling the chemical across the eastbound carriageway.

Two vehicles – the tanker and a Mazda MX5 convertible - have been involved with no serious injuries reported. The problem lies in the recovery of the tanker and its load.

Emergency services are at the scene including officers from Thames Valley and Wiltshire Police forces, ambulance services, the air ambulance and the Environment Agency.

Drivers are being urged to avoid the whole area as the eastbound carriage way is likely to be shut and consideration is being given to closing the motorway in both directions. Drivers traveling in both directions should rethink their routes to avoid the M4.

More information will follow as we have it.