(1)For the purposes of section 768(3), an officer of Revenue and Customs must, if required to do so, produce a certificate specifying—
(a)the amount of income in respect of which tax has been paid, and
(b)the amount of tax paid.
(2)The certificate is conclusive evidence of any facts stated in it.
(3)See also section 944 (under which directions may be given for payments within this Chapter to non-UK residents to be made under deduction of tax).