NIM39625 - National Insurance Numbers (NINOs): Special Cases: NINOs issued in the Channel Islands
NINOs allocated in the Channel Islands have a JY or GY prefix according to where they were issued. If the number was issued in Jersey the prefix is JY and if it was allocated in Guernsey it is GY. These numbers are not valid in the UK unless the customer already has a fully NIRS maintained UK NI account (see NIM39115). Otherwise customers arriving from the Channel Islands and requesting a NINO will need to satisfy the criteria of working or claiming benefit before being able to apply to Jobcentre plus for a UK NINO. See NIM39325.