Falls under Road Traffic Act 1988 and the Road Vehicles (Construction and Use) Regulations 1986.
Generally:
Only authorised constables may test or inspect on the road.
All uniformed constables may test and inspect on premises – subject to conditions.
On road testing (Road Traffic Act 1988 – Section 67)There are two types of authorised examiner – those authorised by a chief constable and those by the Secretary of State. This type of authorised examiner may test on road for:
Brakes
Silencers
Steering Gear
Tyres
Noise
Smoke
Fumes/vapour
Lights and Reflectors
– provided the use would involve danger of injury to any person.
The rider has the option to defer the test when Notice Provisions kick in. A non-authorised person has no power to detain a vehicle unless it is too defective to proceed or post accident.
Broadly speaking you may have a defence if an unauthorised examiner tries to examine your bike for a defect which really needs someone with more knowledge (and is authorised) to diagnose. But that doesn't mean that you are in the clear where the defect is obvious to anyone, for example:
Your exhaust is hanging off
Your tyre is split
Also the requirement in more complex cases for an authorised examiner can be waived by you – so never agree to the officer in question doing that.
Even if the officer is not authorised, he/she may still report it. If you are subsequently prosecuted then it is a question of whether the prosecution has a sufficient weight of evidence – clearly in borderline cases examination by authorised officers will carry much more weight than non-authorised ones.
The test under Section 67 is not just an observational one but is required by an authorised examiner. You may elect to defer the examination to a time and place to be arranged. If (as the rider) you are also the owner you may choose a period of 7 days – within the next 30 days – when the examination may be carried out on premises specified by you. If you are not the owner of the bike you are riding, you must give the owner's address and the examiner must make arrangements with the owner. Two days notice within the 7 day period must be given. If no period is specified then there should be 7 days notice.
Off road testing (Regulation 74)Any constable in uniform or vehicle examiner may inspect:
Brakes
Silencers
Steering gear
Tyres
– On premises – with the consent of the owner of the premises – but the constable has no power of entry.
To summarise:
No consent of owner of premises – no test
No consent of owner of vehicle – no test unless:
Within 48 hours of accident.
Notice served – 48 hours personal notice / 72 hours recorded notice.
Testing and inspectionCANNOT be carried out without the consent of the owner – unless 48 hours personal notice or 72 hours recorded delivery notice has been given – but NB the owner consent is not required if the vehicle has been involved in an accident within the last 48 hours.
If an owner/rider is seen driving a defective vehicle but an officer is not in a position to stop that vehicle, the officer cannot pursue the vehicle which is then garaged on home premises and where no consent to inspect is given. However if it is garaged on garage premises then the vehicle can be examined – either with the consent of the garage proprietor – or after giving the appropriate notice.