Chesterfield's May Day Parade and Gala celebrations is a chance for all Lefties of all persuasion to get together, march around town and get together for speeches, music, lefty talk  and general bonhomie.  It's  been going since 1978, a film of which you can watch for Free on BFI Player. I'm sure my late Dad is on it stood by the side of the road near the Town Hall. I'm sure it's him and I reckon I was there too. 
It's a great day out if you like that sort of thing, being a bit of a lefty myself and a great opportunity with the camera. I've been documenting it now for a few years and I've got a metallic badge for every year I've been. I'm trying to get the full set.