Are Velomobiles street legal in the UK?
References: Bikehub - Cycling and the Law, Traffic Signs Regulations and General Directions 1994, Road Vehicles Lighting Regulations 1989

A velomobile or recumbent bike is covered by the same law as regular bicycles:


  "pedal cycle" means a unicycle, bicycle, tricycle, or cycle having four or more wheels, not being in any case mechanically propelled unless it is an electrically assisted pedal cycle of such class as is to be treated as not being a motor vehicle


So it's legal to use to ride one on the road in the UK.

Cycle paths are a bit more complicated as some legislation refers to "bicycles" and some to "pedal cycles", so it would depend on how many wheels you've got and what type of cycle path / cycle lane / cycle track you wanted to use.

If you want to use a velomobile or recumbent bike on the road between sunset and sunrise then you may have problems. To be legal you'd need 2 pedal reflectors on each pedal and these have to be clearly visible from the front and rear. The design of most velomobiles and recumbent bikes do not meet this requirement. This law is rarely (if ever) enforced, I think your main worry on this point is if you were involved in an accident then the other party might try to use your lack of reflectors to show negligence.

Note - If your velomobile or recumbent bike is electrically powered then there are additional regulations that must be complied with, but I think that's beyond the scope of the question.