A licence is needed to fish for the baby eels along the River Severn

A number of agencies have joined together for the first time to catch unlicensed fishermen who try to cheat the system with illegal trawling nets.

Patrols will be looking for illegal equipment, which can harm the eels or give fishermen an unfair advantage.

Elvers, or baby eels, can fetch as much as �300 a kilo in the UK and in countries such as China and Japan.

The Environment Agency, Gloucestershire Police, British Waterways and Gloucester City Council are involved in the initiative.

Officials warn that any fishermen caught without a licence could face a fine or even be sent to prison.

An annual licence costs �20.