DJK,
May be it would be easy to liken the scenario that people want an answer for to the following:
Imagine your wife is 39 weeks pregnant and you think you may have to take her to hospital and you think you may well not make it if you stick to the speed limit.
Do you think you can find any copper/judge to give you carte blanche for breaking the speed limit if you ring them and ask?
Methinks not.
FD