UK National Agency for the ISIL
The International Standard Identifier for Libraries and related organisations.
The ISIL is the International Standard Identifier  that can be assigned to a library or related organisation. An ISIL can also be assigned to sub-units of an organisation.
In 2007 the British Library became the UK National Agency for the assignment of the ISIL to organisations in the United Kingdom, Crown Dependencies and Overseas Territories.
ISILs assigned to libraries by the British Library are based on MARC organisation codes which are made globally unique by the addition of a country code prefix (ISO 3166-1).
How to obtain an ISIL
Please contact us at the following e-mail address firstname.lastname@example.org to request a code.
Requests for an ISIL for one organisation will be processed within a few days.
If you require codes for more than one organisation, or for multiple sub-units of one organisation, this processing will take longer depending on the overall number and will be assessed on a case-by-case basis. Please contact us at the above e-mail address to discuss.
We are working on providing a searchable database of ISILs assigned by the British Library.
ISILs are 16-character variable length codes which uniquely identify libraries and related organisations in an international context. They can accommodate existing national library identification systems.
The Danish National Library Authority is the International Authority for the registration and maintenance of the standard. Its role is to maintain a source of information about the National Agencies involved and to supervise the use of country and non-country prefixes. It also has a promotional role.
More details about the ISIL are available from the ISIL Registration Authority.
 ISO 15511:2003
For further information please contact:
The British Library
Boston Spa, Wetherby
Tel: + 44 (0) 1937 546124
Fax: + 44 (0) 1937 546586