The Leach runs through the Cotswolds — limestone-influenced, clear, spring-fed, moving through stone-walled country with the unhurried pace that chalk-influenced water has. It passes through Eastleach, where there's a clapper bridge worth seeing whether or not the fishing is the reason you came. Wild brown trout throughout, mostly in the tight bends where undercut banks give them depth and the current concentrates their food. Small-river chalk stream fishing, which means one fish properly approached matters more than ten covered carelessly.

• Limestone