You need permission from Thames Water to dive here. This includes various restrictions such as A flags and probably not in high season!
The attraction of this dive is what you can find here. We pulled out a pistol from here!
My buddy was scared out of his wetsuit when a 3 foot sturgeon(?) jumped out of a shopping trolley he disturbed.
Facts about Chertsey Bridge

• It is in United Kingdom
• The typical depth is 0-10 Metres 0-30 Feet.
• The typical visibility is 0-3 Metres 0-10 Feet.