When you make a claim on your insurance, even if your no claims is protected it could be reduced by 2 years.
If they are not protected, you could lose them altogether.
It could take at least 12 months for your insurer to recover all of their losses and only if they do will your no claims be unaffected.
Regardless of no claims bonus, your premium may still increase anywhere between 20% – 50% as any accident is seen as a future risk by insurers and could affect you for the next 5 years.
Insurers ask about previous claims history over this period when renewing.