Sch 11 para 4
(1) The Commissioners may, as a condition of allowing or repaying input tax to any person, require the production of such evidence relating to VAT as they may specify. (1A) If they think it necessary for the protection of the revenue, the Commissioners may require, as a condition of making any VAT credit, the giving of such security for the amount of the payment as appears to them appropriate. (2) If they think it necessary for the protection of the revenue, the Commissioners may require a taxable person, as a condition of his supplying or being supplied with goods or services under a taxable supply, to give security, or further security, for the payment of any VAT that is or may become due from— (a) the taxable person, or (b) any person by or to whom relevant goods or services are supplied. (3) In sub-paragraph (2) above “ relevant goods or services ” means goods or services supplied by or to the taxable person. (4) Security under sub-paragraph (2) above shall be of such amount, and shall be given in such manner, as the Commissioners may determine. (5) The powers conferred on the Commissioners by sub-paragraph (2) above are without prejudice to their powers under section 48(7).