VIT51200 | Motoring expenses: motor caravans
From HM Revenue & Customs · VAT Input Tax
HMRC has agreed with the Society of Motor Manufacturers and Traders that all these features must be found in a vehicle for it to be treated as a motor caravan:
a permanently installed sink and cooking facilities;
seating arrangements that let diners sit at the meal table;
at least one bed which is no shorter than 1.82 metres; and
a permanently installed fresh water tank with a minimum capacity of ten litres.
A motor caravan is not a car.