So, you catch a 'thief'...

I don't know. I guess the answer is find/call a police officer and ask them to intervene.

Call a police officer, what number would you call ? 999 would not consider a possible bike being stolen an emergency in any way whatsoever. The number of your local police station will ring and ring for hours (I do not exaggerate here - hours, not minutes) if it is answered at all as on the front desk is usually just a single desk sergeant who has to deal with everything.

I know this from spending more than a few days in police stations over the years reporting my bikes stolen (10-ish so far) - if the phone rings no one will answer it, it is as simple as that, it's actually quite an annoying atmosphere to be in with an endlessly ringing phone.

I once had my bike stolen (one of many) and chased the bastard from Kentish town road to the corner of Camden Road, imagine my relief when I almost crashed into a policeman, out of breath I pointed to the bloke going off into the distance and told the copper that was my bike and it had just been stolen - what did he do ? Did he put out a call to any cars in the direction the bike was going ?

No, he told me that I am unlikely to get it back and got his note pad out and started to fill out a crime report - this is as the bloke on my bike was still visable !!

The police are not interested in bike theft, it is not a priority, this is evident by the epidemic of bike theft and the increasingly brazen attitude of bike thieves.

I recently saw a group of 5 or 6 kids with a pair of those long bolt croppers stealing a bike just off Belsize lane, no way was I going to stop them, it was in a quiet street and they looked like the sorts who would stab you for your phone, so I watched from a distance and - of course - phoned Hampstead police station - listened to around 5 minutes of ringing - they stole the bike - listened to around another 10 minutes of ringing - I hung up and went home.

If anyone here has reported a bike stolen in a police station you might start to get an idea of how bikes are seen by the law. On the description form you are asked whether your bike has rod brakes (yes those old solid rod brakes that have not been in use since the 1950s/1960s) - what kind of bell you have - handlebar mounted ? What kind of fenders you have - chrome or painted and so on - to some poor bastard who has just lost his posh mountain bike with disc brakes and a suspension fork it is like trying to point out his carbon fibre baby in the 1948 Raleigh catalogue - useless outdated madness.

I am rambling a bit here now, but what I am trying to say is that the police are not the answer.