Presumption of unfitness to drive.

In any proceeding for an offence punishable under section 185 if it is proved that the accused, when requested by a police officer at any time so to do, had refused, omitted or failed to consent to the taking of or providing a specimen of his breath for a breath test or a specimen of his blood for a laboratory test, his refusal, omission or failure may, unless reasonable cause therefor is shown, be presumed to be a circumstance supporting any evidence given on behalf of the prosecution, or rebutting any evidence given on behalf of the defence, with respect to his condition at that time.