The voucher must not be worth more than the basket value (minus shipping costs). Otherwise, the voucher value only corresponds to that of the product and the remainder expires.

Example: The product costs £9.95. There is also £7.90 shipping. If a £10 discount voucher is applied to this purchase, only the shipping costs of £7.90 will be charged. The £0.05 by which the product is worth less than the voucher expires.