‘Thieves are getting smarter,’ a bike mechanic told me. ‘They know what’s expensive and they look for these parts.’ He showed me a pair of gear shifters worth £900, which could be removed relatively easily: you just need to unscrew the stem bolt and cut through the brake cables. That’s what happened to my bicycle last year (my shifters would have fetched much less than £900). The mechanic never parks his bike outside: ‘I don’t even have a lock.’