I don't think in any insurance policy you need to have ESP on... The list would be pretty long - ESP, ASR, ESR etc and many more
Paul
Greenlight dont insure cars that lack ABS, but esp been off, im not sure, it would depend on the circumstances of the crash surely.
If you lost control and had esp off then maybe but as Rich says once the car has been turned off the esp turns back on.
Would be very difficult to prove that one me thinks, unless you disabled it in vagcom.