Of course you could bolt it on once a year for the MoT and then put your bad ass postage stamp back on. However, on the few occasions a road traffic officer is close by, they will be drawn to you like a fly to ordure.
The rules are quite prescriptive – in fact so prescriptive that unless your plate is obviously illegal, most coppers will ignore minor breaches.
In reality these rules specify height of letters and distances between them so if you want a small but legal number plate get one with plenty of number 1’s and letter Ts. All other letters and numbers must be 44mm wide and the gap must be 10mm which is smaller than a car’s: I once broke a plate on my dirt bike and had the genius idea of getting a new one made at an agricultural engineers so I could legally ride home. I can tell you tractor plates are huge. Yet I was inadvertently breaking the law because there is one size for a motorcycle number plate, and that is not tractor size.
The size of the number plate, so long as it is on a BS Approved reflective yellow plate and the numbers are all the right size and correct distance apart, is not set in law anywhere and there is nothing at all unlawful about having a small plate so long as it meets the lettering and spacing requirements.
But what about all the little dodges? The strategically placed fixing bolts that turn an 1 into a T or a ‘5’ made to look like an ‘S’ so it can spell out some hieroglyphical version of your name or your bike? That is a level 3 fine – up to £1000 – but most officers will give you words of warning and probably a rectification notice unless the intention looks to be to avoid speed cameras and ANPR in which case they can get a lot grumpier.
If you keep doing it you get to have your number plate taken from you (the Secretary of State allocates your vehicle a number and s/he can take it back if you keep messing with it) and it will be replaced with a ‘Q’ plate which doesn’t do your resale value much good.
As to chow plates – these do not meet British Standards and the show plates will neither have BS nor supplier markings. For those of us who ride off road a flexi plate is a good idea, otherwise we end up leaving bits of bright yellow Perspex littering the countryside. But, good idea or not, it is illegal.
In my many years of goofing about on the byways of England and Wales with a non BS, correctly proportioned, bright yellow and reflective flexiplate I have had zero police attention. Mates on little 3-row plates with numbers best used in an optician’s test do not fare so well. The 3 rows issue is not particularly well known, but a number plate for a motorcycle registered after 2001 must be on 2 lines.
For muddy weekend warriors it is an offence to have your number plate obscured with mud (or anything else) but it is a defence to show you have not had the oportunity to clean it.
Bike Magazine August 2022