On a wet Wednesday in April, spent picking litter and spotting sewage in the River Wandle in Merton, south London, the Lib Dems look beside themselves with enthusiasm.
Ed Davey, the Lib Dem leader, is here to rally his activists with a speech highlighting Tory failures to clean up Britain’s waterways. He arrives in a sharp suit to deliver his party’s local election launch to waiting TV cameras, before gamely changing into wellies for a photo op in the water.
