wrote:
According to
http://www.cl.cam.ac.uk/research/dtg...cgi?2006_10_06
can anyone back that up?

Not quite. I am about 18 kms to the southwest of Cambridge. As the
cold front came through, there were two bursts of phenomenal rain with
a short gap between. I recorded about 7 mms in as many minutes, but
the day total was only 10 mms. However, I could well imagine that had
the shower distribution been very slightly different, we could easily
have got the sort of figure you are quoting. It really was one of the
most intense rainfalls I have seen. I watched from quite close
quarters in fact. I had just gone to the garage and was "trapped"
inside for those 7 minutes.

Jack