Automatic motorbike

[JohnnyGus]

How common are motorcycles with automatic transmission in Britain?

[RocketRon]

Not Very - I've never encountered one, although I'm not a biker :-)

[ianess]

MV Agusta did a big [900cc I think] automatic motorcycle way back in the late 60s or 70s but it never caught on at all, possibly because of the "Rolls Royce" reputation of the marque.
Nearly all scooters are automatic nowadays and  Suzuki with their Burgman models and the Honda Silverwing are fully automatic superscooters that are more like touring motorcycles. There may be others from about 400cc upwards.

[Vijz]

ianess's answer is good re. the scooters; there are also Honda C90s and the like which are semi-automatic.

Honda used (a long time ago) to have an Dream 400AT that was a parallel twin automtic, but it was never very popular, and was not in their model range very long.