VFR11010 | Procedure tables: supplies of goods by UK traders for the official use of visiting NATO forces - VAT aspects
From HM Revenue & Customs · VAT Visiting Force Relief Manual
Compliance officers visiting VAT registered businesses that have supplied goods to visiting NATO forces in the UK should check that:
VAT free supplies to US forces in the UK are covered by an official contract or purchase order signed by a properly authorised signatory of the US forces, containing the certificate and official receipt in accordance with VFR03100 (‘Procedures for US forces official purchases’ heading);
supplies to non-US forces have been charged with VAT at the normal rate unless the exemptions in VFR03200 (‘Liability of suppliers’ heading) apply;
Businesses operating under a concessionaire contract with the US forces in the UK are dealt with under the procedures in VFR12030.