23.—(1) In a prosecution of a person for an offence under section 13 for refusing or failing to comply with a requirement to provide 2 specimens of his breath, it shall be a defence for the defendant to satisfy the court that there was a special and substantial reason for his refusal or failure and that, as soon as practicable after the refusal or failure concerned, he complied (or offered, but was not called upon, to comply) with a requirement under the section concerned in relation to the taking of a specimen of blood or the provision of a specimen of urine.

(2) In a prosecution of a person for an offence under section 13, 14 or 15 for refusing or failing to comply with a requirement to permit a F26[designated doctor or designated nurse] to take a specimen of blood or for refusing or failing to comply with a requirement of a F26[designated doctor or designated nurse] in relation to the taking of a specimen of blood, it shall be a defence for the defendant to satisfy the court that there was a special and substantial reason for his refusal or failure and that, as soon as practicable after the refusal or failure concerned, he complied (or offered, but was not called upon, to comply) with a requirement under the section concerned in relation to the provision of a specimen of urine.

(3) Notwithstanding subsections (1) and (2), evidence may be given at the hearing of a charge of an offence under section 49 or 50 of the Principal Act that the defendant refused or failed to comply with a requirement to provide 2 specimens of his breath, or that the defendant refused or failed to comply with a requirement to permit the taking of a specimen of his blood or to comply with a requirement of a F26[designated doctor or designated nurse] in relation to the taking of a specimen of blood, as the case may be.