UK car accident: do I have to tell the police and my insurer?

GOV.UK says you must report the accident to police within 24 hours if you did not give your details at the scene. You must also report the accident to your insurer even if you do not intend to make a claim. Keep names, addresses, registration details, photos and witness information. Official source: GOV.UK Vehicle insurance — if you’re in an accident. Guide: https://getinstantlaw.com/car-accidents/insurance-claim-denied