Is there any significance in the format of a National Insurance number?Thursday, October 28th, 2010
National Insurance numbers are allocated by the Department for Work and Pensions (DWP) and, in the context of payroll, are the reference number by which HMRC identifies each individual’s income tax account and National Insurance contribution record. The number is a critical data item in each employee’s payroll record. It is used by DWP in managing state benefits, local councils in managing housing benefit, the Student Loan Company is managing student loans, and by banks and financial institutions in connect with Individual Savings Accounts (ISAs).
A National Insurance (NI) number (often referred to as a ‘NINO’) is allocated to a child when a Child Benefit record is created for that child. At that time, the number is known as a Child Reference Number (CRN). Before the child reaches school-leaving age, the CRN becomes an NI number. The number was issued for many years by means of an NI number card but is now issued by letter.
An NI number has three parts, a two-character prefix (e.g. AB), a six-digit number, (e.g. 123456) and a single-character suffix (e.g. C), making up the full number AB123456C. None of the three parts has any personal relevance to the individual to whom it is allocated. The prefix, however, can be used to determine the year in which the NI number was created and some prefixes are specific to certain areas of the UK, such as JY for Jersey, MN for Isle of Man and BT for Northern Ireland.
The prefix is a combination of most letters of the alphabet. The letters D, F, I, Q, U and V are not used at all in order to avoid confusion with other letters if badly written. The letter O is not used as the second letter of the prefix to avoid confusing it with zero. The prefix is the only part of the NI number that can be validated when the number for a new employee is recorded in a computerised payroll system or when HMRC receives P14 End of Year Summaries. The only prefixes that may be used are those that have already been allocated. Payroll system developers are informed of the prefixes that have been allocated or that are currently being allocated.
Some prefix combinations have been used at times for temporary purposes. Prefixes such as ‘00’ (used for tax credit purposes), ‘NC’ (used for stakeholder pension purposes), and ‘TN’ (historically used by employers when a new employee was unable to provide a correct NI number) are not permitted on any returns or forms sent to HMRC.
The central part of the NI number is a number between 000001 and 999999. There are, therefore, almost one million numbers that can be used with each prefix. New NI numbers are allocated consecutively, so AB000001A would be followed by AB000002B, AB000003C, AB000004D, AB000005A, and so on.
The suffix letter, A, B, C or D, has no current relevance at all. In fact, if an NI number is shown on a document sent to HMRC with the suffix missing, it will still pass the validation test.
The suffix letters, however, have an interesting history. Prior to 1975, National Insurance contributions were collected by means of small stamps that were purchased at post offices and affixed to a National Insurance contribution card that the employer kept for each employee. Each card would be full after a year, after which the card had to be sent to the DSS (the forerunner of the current DWP) in exchange for a new card. The suffix letter told the employer when to return each card, in March for suffix ‘A’, June for suffix ‘B’, September for suffix ‘C’, and December for suffix ‘D’. Although contribution cards are no longer used, the suffix is still an integral part of the NI number.
A correspondent recently asked why, if NI numbers are allocated consecutively, her two children, born several years apart, have consecutive numbers, e.g. AB000001A and AB000002B (not the actual numbers). In fact, two of the author’s children, although born seven years apart, have consecutive NI numbers. Another situation that arises at times is that two people who were in the same school class together find that they also have consecutive numbers.
Historically, NI Number prefixes were allocated regionally and the period over which they were issued varied considerably. In October 1988, a national system of prefixes was introduced and, in 1992, as a part of the process, a CRN was allocated in bulk to every child in the Child Benefit system at the time.
Prior to 1992, an NI number was allocated to each child at about the time the child turned 16. The numbers were allocated from school records, so children whose names were next to each other alphabetically in the class register will often have consecutive NI numbers.
In 1992, when a CRN was allocated to every child for whom Child Benefit was in payment, the children in a particular family were, in many cases, allocated consecutive numbers. Therefore, families who were in receipt of Child Benefit for two or more children in 1992 may find that their children have consecutive NI numbers.