From that site:
The law requires children (and adults) travelling in the front of all vehicles, including vans, buses, coaches, minibuses and goods vehicles to use an appropriate child restraint or adult seat belts.
Summary of the Seat Belt Laws for front seat
Children under 3 years old - Correct child restraint MUST be used in front and back of a car. If one is not available in a taxi, then the child may travel unrestrained in the rear. Driver's responsibility
Children aged 3 and above, until they reach EITHER their 12th birthday OR 135cm in height = Correct child restraint MUST be used in front. Where seat belts fitted in back, correct child restraint MUST be used
MUST use adult belt if the correct child restraint is not available in three scenarios:
- in a in a licensed taxi or private hire vehicle ;
- for a short distance for reason of unexpected necessity;
- two occupied child restraints prevent fitment of a third.
In addition, a child 3 and over may travel unrestrained in the rear seat of a vehicle if seat belts are not available
Driver is responsible
Child over 1.35 metres, or 12 to 13 years Seat belt MUST be worn in front, if available Seat belt MUST be worn in rear, if available Driver is responsible