This has nothing to do with Diplomatic Immunity
What it is about is whether this act
http://www.law.berkeley.edu/faculty/...s/rp04038.html contravenes this act
http://www.opsi.gov.uk/ACTS/acts1998/19980042.htm (the house decided that it did not)
I haven't read the judgement but I am not surprised at the decision.
If any of you want to read the judgement it it is here
http://www.publications.parliament.u...14/jones-1.htm
EDIT: all 5 law lords were in agreement which is usually a pretty good indication that the decision was a good one