It may still be possible to bring a claim even if you are not able to ascertain the registration number of the vehicle at fault. However section 34 of the Motor Accident Compensation Act 1999 provides that the Insurer can reject the claim for failure to make due search and enquiry to establish the identity of the vehicle. It is essential you seek legal advice as soon as possible after suffering an injury in a motor vehicle if you are unable to identify the vehicle at fault in the accident to ensure you comply with section 34.