The cause of a huge explosion that has lit up the night and been seen by thousands has been revealed, as emergency services have raced to the scene.

People far and wide across Oxfordshire have seen what appears to have been a fireball near the A34 this evening after a lightning strike.

The incident near Yarnton was confirmed as a bolt of lightning hitting a gas tank at the Cassington AD Facility at around 7.20pm.

A spokesman for Severn Trent Green Power, which runs the site, said: "We can confirm that at around 7.20pm this evening, a digester tank at its Cassington AD facility near Yarnton, Oxfordshire, was struck by lightning resulting in the biogas within that tank igniting. 

"We are working with the emergency services to secure the site and will provide further comments in due course."

Thames Valley Police has confirmed officers are on the scene of a fire at a waste plant. 

A statement from the force said: "It is believed that lightning struck gas containers at the site during bad weather this evening, causing a large fire."

It is not clear yet if anyone has been injured in the incident.