If you are unfortunate enough to be involved in an accident contact your insurance company as soon as possible, even if you are intending not to make a claim on your insurance.
If you're involved in a road traffic accident that isn't your fault you have the right to claim back losses from the responsible party. This should not impact your no claims bounus as it was not your fault.
Did you know that if you drive abroad your fully comprehensive insurance could be downgraded to basic third party. So if you intend to drive abroad you may want to take out extra cover.