Failure to provide a specimen of breath can result in:
Failing to provide a specimen of breath for a breath test
Failing to provide a specimen for analysis or laboratory test
(a) When driving or attempting to drive: six months or £5,000 or both
(b) In any other case: three months or £2,500 or both
A popular defence to the charge failing to provide a specimen of breath is based on the defence of "reasonable excuse". This defence is based on medical evidence and should be provided before the hearing. If necessary, expert medical evidence is obtained which addresses the specific issues raised by the defence. In (DPP v Crofton (1994) RTR 265) it was held that the Court should consider the following matters in such circumstances:
Once such a defence is raised, the onus is upon the prosecution to negate it.
When your reading is between 40 and 50 a driver may choose to replace a breath specimen by supplying a blood or urine sample (section 8(2) of the Road Traffic Act 1988). The police:
If the officer has failed to inform the driver of his option to have a blood or urine test you will be acquitted of the relevant allegation.
The first generation of Evidential Breath Testing Instruments (EBTIs)were replaced in 1999. All forces are now equipped with the Intoximeter EC/IR, the Camic Datamaster or the Lion Intoxylizer 6000UK. They detect and record a wider range of information when analysing breath samples.
These three makes of instrument are type approved by the Secretary of State for the purposes of the Road Traffic Act. Any challenge of that type approval must be made by way of an application for Judicial Review, not in the course of a summary trial relating to the performance of a particular instrument: (see DPP -v- Brown and DPP -v- Teixeira  EWHC Admin 932, 166 JP 1)
In the case of a breath specimen there is a statutory assumption at section 15 RTA that the instrument concerned performed reliably. However, that assumption may be challenged by evidence relevant to the circumstances of that particular case. In order to convict in the face of such evidence the Court must remain satisfied that the instrument provided a reading upon which they can rely. See Cracknell -v- Willis (1998) 1AC 450 at 467, and DPP -v- Brown; DPP -v- Teixeira.