Hundreds of emergency service workers have rehearsed their response to a possible chemical attack at a beer festival in Bristol.

A number of "casualties" were seen lying in Millennium Square.

Police said the crews were rehearsing their response to a deliberate release of chemical agents, resulting in several casualties.

In the scenario, there has been an explosion, people have been injured and a chemical is believed to have been released into the atmosphere.

Avon and Somerset Police, Great Western Ambulance Service, Avon Fire and Rescue Service and Bristol City Council workers were present.