(1) A payment transaction is to be regarded as having been authorised by the payer for the purposes of this Part only if the payer has given its consent to -
(a) the execution of the payment transaction; or
(b) the execution of a series of payment transactions of which that payment transaction forms part.
(2) Such consent -
(a) may be given before or, if agreed between the payer and its payment service provider, after the execution of the payment transaction; and
(b) must be given in the form, and in accordance with the procedure, agreed between the payer and its payment service provider.
(3) The payer may withdraw its consent to a payment transaction at any time before the point at which the payment order can no longer be revoked under regulation 67.
(4) Subject to regulation 67(3) to (5), the payer may withdraw its consent to the execution of a series of payment transactions at any time with the effect that any future payment transactions are not regarded as authorised for the p