The Motor Vehicles (Wearing of Seat Belts) Regulations 1993
(Basically states an adult in the rear of a vehicle must wear a seat belt if fitted, so carriage of passengers on side facing seats is not illegal
under this regulation).
EC Directive 2005/39/EC states that travel in sideways facing seats with a seat belt is unsafe and that from October 20th 2007, it will not be possible to travel in them in
new motorhomes. This legislation is not retrospective so
vehicles registered before 20th October 2007, do not have to have seat belts fitted in the rear.
This is the law that introduces passengers must be only be carried in belted seats which face forward or rearward. These seats have to be designated by the manufacturer as travelling seats and are supposed to be signed with a badge stating this. Again not illegal for older motorhomes, but the introduction of the
'unsafe' aspect of this type of travelling is introduced....I would expect this to be tied down firmly as illegal in all cases in the near future.
The law that will catch you regardless:
Regulation 100(1) of the Road Vehicles Construction and Use Regulations 1986 and Section 40A of the Road Traffic Act 1988 state that : "A person is guilty of an offence if he uses, or causes or permits another to use a motor vehicle or trailer on a road when a) the condition of the motor vehicle or trailer or of its accessories or equipment or b) the purpose for which it is used,
or c) the number of passengers carried by it or the manner in which they are carried or d) the weight, position or distribution of its load or the manner in which it is secures, is such that the use of the motor vehicle or trailer involves a danger of injury to any person."
This was primarily intended for the white van goods vehicle which was carrying several people in the rear where there were no passenger
seats, but is also used by police as an unrestrained passenger becomes an internal missile in the event of an emergency stop or an accident.
This is also the regulation which
Insurance companies might use to avoid a claim, and that is something you would need to clarify with your
insurance company if it is your intention to carry unrestrained passengers on side facing seats in an older motorhome.
Of course there are excemptions to this for people with medical conditions and for emergency services etc., but for the majority of us we fall
foul of in one case we can use the side facing seats, and in another we are open to prosecution and possibly left to pay compensation personally.
(I am also certain I read legislation for the UK stating that passengers had to be carried on forward facing seats only...but I haven't been
able to pin point the actual text I read for this post).