My bike getting stolen

I was coming home one day. As I was walking along the front of the house towards the main door, I noticed something - or rather - a lack of something. My bike was not there. I had left it locked to a railing in front of the house couple of days ago but now it was not there. I stopped for a moment and pondered whether I had not left it somewhere else. No. I knew I left it in front of the house. My bike got stolen.

House Jesus Lane 34. I locked my bike to the black railing.

I looked on the ground and saw my cable lock. It had had been cut. ”Oh no,”  I thought. I should have replaced it sooner. I knew my lock had been damaged. Several weeks before I noticed a little rusty notch in the cable. Someone started sawing through the cable but stopped half-way through. Something scared him off, presumably. Now they came back and finished the job. Had I bought the new cable lock, I would still have my bike. However, a careful examination of the lock showed that it had been cut in a different place. The rusty notch was still there! I felt bit relieved now because I have just saved money by not buying a new cable lock, which would have been destroyed anyway.

Bicycle theft at Cambridge is among the highest in the whole of the UK. The chances of recovering a stolen bike are next to nothing. Despite these grave facts, I had hope. The reason was a CCTV camera mounted right in front of my house overseeing the T Junction of Malcolm Street and Jesus Lane. Surely, it must have recorded the crime.

View from my room. A CCTV camera can be seen on the other side of the street.

I went to the Police station next day. I came up to the counter as I was saying, "Hello, I would like to report a bike theft," I placed  a cut cable lock importantly on the counter like a king who takes his crown from his head and places it on a carmine pillow with golden lining before going to sleep. I think my outstanding bit of acting came across very well as I was told to go to a little cubicle and report the crime via a land-line phone in the room.

I entered the little room and sat down on a chair. After ten minutes of waiting for the phone to ring, I realised that perhaps I should pick up the phone and start speaking. So I did that and it worked. I was actually slightly disappointed that I was not speaking to someone face to face because I brought pictures of the crime scene, of my bike etc. When I thought it was the right time, I said:

 "There is a CCTV camera right in front of my house, which must have recorded the crime. I was wondering if could not investigate that."
"What was the last time you can guarantee you have seen your bike?"
"Saturday evening." I noticed my bike missing on Monday late evening.
"I am sorry sir, but that gives a period longer than 4h. We only look at the footage if the time-span is shorter than 4h."

How unbelievably idiotic I thought. What an insanely moronic approach. Given that the parked bike is a stationary object, one does not have to watch through 48h of footage to find when it got stolen. One can just look at couple of seconds in the middle of the time period and see if it is there. If the bike is still there, it is clear that It had not been stolen in the first 24h. It took only couple of seconds  of footage in the middle to halve the possible search space. Same approach can be applied iteratively on the remaining time interval. This method is called a binary search because each time you evaluate 'objective function' - objective function being in this case 'is the bike there' - you halve the search space. You can use a very similar method called 'Golden ratio bisection' which is slightly faster but I will not go into that.

"What do you mean the time span is too long? It would take you only a couple of minutes to reduce the search time to 4h."
"I am sorry sir, that is the policy."
"I don't like this policy. Who can I complain to about it? If it takes too much time, I am happy to help you. Just give me access to that footage and I will find it for you."
"I am sorry but that is not possible."
"Who can I talk to about it?"
"The local council owns all the footage, you should speak to them."
"Thank you."

Sometimes, I wish I were tougher on people. I do not think I was assertive enough. I left the Police station and started googling this 4h policy. I was really surprised with the results. I found this article  where the new Cambridge Police chief explains how watching CCTV footage in the context of a bike theft is a not an 'efficient use of Police time'. It says that the quality is often not good enough to provide an unshakable identification of a convict. Wait....WHAT? If you cannot identify a person using a CCTV camera, why on Earth do you have them? Are they only good enough for being able to read a number-plate of a car jumping a red light?

RIP my old bike.

What made me most upset about the whole incident was the approach of the Police: refusing to look at the footage which, according to the Police chief is usually useless anyway. I struggled to believe this. The bike I lost was a low quality anyway. A friend of mine gave it to me since he was not using it. I bought the same bike in my fresher year for £120, so I still had my old bike. The shifters did not work properly but apart from that it was alright. I did not go to the local city council. I had exams so I have lost the determination to continue.

What remains to be said? One needs to care about policies of a place... so that one is not flabbergasted that CCTV does not actually protect us from what we think it does.