They're not the only ones creating barcodes -- stamps come with non-specific data, but bulk mailers are allowed to create their own, with embedded routing and b

They're not the only ones creating barcodes -- stamps come with non-specific data, but bulk mailers are allowed to create their own, with embedded routing and billing codes. The spec is here: https://www.royalmail.com/sites/default/files/Royal-Mail-Mailmark-barcode-definition-document-September-2015.pdf https://www.royalmail.com/sites/default/files/Royal-Mail-Mai...