Sadly a lot of British 'manufacturers' are actually designers and importers. The following are ,I believe , 'made in Britain' (HOPE - stems, seatposts, clamps, brakes, levers, chainrings, QR, headsets
USE - chainrings, stems, seatposts, bars, bottle cages, QR
MIDDLEBURN - chainrings, cranks, hubs, valve caps
GOLDTEC/BETD - hubs, chainrings and suspension upgrades
BROOKS - saddles, grips
Frames - Orange used to make some of their top end frames here. Apart from bespoke frame builders are there any 'big' manufacturers left actually building in the UK?