Section 172 of the Road Traffic Act, 1988, gives the police power to serve notice upon the registered keepers of vehicles, to whom the section applies, of a requirement to identify the driver at the time of an alleged offence.
If you were the driver of the vehicle at the time of the alleged offence you are required to complete part 1 of the Section 172 statement.
If you were not the driver of the vehicle at the time of the alleged offence, you are required to give any information in your power which may lead to the drivers identification by completing the appropriate part of the Section 172 statement.