You will of course recall my recent post on Big Data in which I related how many laptops are left in the back of taxis. 10,857.14 of them every year to be precise. Well I was wrong. Not only did I underestimate how many cabs there are in London but the average number of laptops left in them every year was wrong.

Today I was picked up by a driver who estimated he had found 8 laptops over the last 5 years (up from the previous 4 in 7) and that there were around 25,000 black cabs in London (up from 16,000).

This bumps up the averages. To  make it easy on myself if I assume only one a year that suggests that 25,000 laptops are left in London black cabs every year.

Now I know someone will pipe up and say that this is not very scientific and