Nielsen of London
There are over 160 ISBN agencies across the globe each with a responsibility for assigning a unique ISBN to new books published within their region. In the UK and Ireland that role is performed by Nielsen of London
Their contact details are
Tel + 44 (0) 1483 712 215
Fax + 44 (0) 1483 712 215
As a self-publisher you will almost certainly want a block of ten numbers – you cannot have less and are unlikely to require 100 at this stage! The fee for ten numbers is £144 (October 2015) including VAT. You can register online by navigating to the ‘Service for New Publishers’ page on the Nielsen website. The completed form can be either scanned and emailed to isbn.agency@nielsen, faxed to the above number or posted to the address on the form. Within ten working days you will receive your ten ISBNs by email. A fast track service is available on payment of an additional fee.
You cannot apply for your ISBNs until your book is complete because the form requires information such as the physical size of the book, the number of pages and illustrations, the date of publication and the price. However when designing your book cover you must leave space for the ISBN which goes in the copyright page and above the bar code on the back of the book