Skidded on black ice and hit a lamp post, how would that affect my insurance?

Do you have comprehensive insurance and is there any damage done to your mum's car that you would like to get sorted through your insurance policy?

Yes I have comprehensive cover and the car is a write off.

Since you're fully comp, you can put a claim in and the insurance will pay out. You will need to make the claim though not your mum because you were the one driving at the time of the accident. However, your mum will lose no claims bonus as she is the policy holder. You, as a named driver, don't get any NCD as such, only the main driver does.