How accurate is the British Crime Survey?

A number of times now, a few people have remarked to me that the British Crime Survey (BCS) is a much more accurate guage of crime than police recorded crime which is what we use.  They’re free to think that of course, but I’m always a bit surprised and disappointed to find out that they have no idea how the BCS is calculated. What is it about people who more fervently believe something they don’t actually understand?

Anyway, here is a brief explanation of the BCS compared to what we do;

All crime statistics have 3 components; the i) victim i) the crime and iii) the criminal.

What the BCS does is focus a select group of victims (i) and asks around 50,000 victims living in private households about the crimes they have experienced in the last year.
What we do is take the recorded crimes (ii) by the 43 Police Forces in England and Wales, their category, their location and feed all 500,000 into a database once a month.
So the BCS is about the perception of crime from a victims point of view – useful of course but a much smaller and less factual sample. What our data does is strictly evidential, unless you think the Police are making up the crimes, their location and category !