Children Over 3 Years Old up to 135cms in height (approx 4' 5") or 12th birthday whichever they reach first.
If a vehicle has no seat belts, a child aged 3 years and over may travel in a rear seat unrestrained but never in the front seat without seat belts.
Children Under 3 Years Old
A child under 3 years old may not travel in cars, vans or goods vehicles which do not have seat belts installed. If there are no seat belts fitted in the vehicle, then a child under 3 years old may not travel in it.