Car Seat Laws
Seatbelts save lives. And now wearing seatbelts is the law. Why? According AA Motoring Trust, "Ensuring a child is properly restrained in a child car seat can reduce injuries by a factor of 90-95% for rear facing seats and 60% for forward facing seats"

Now it's EU law: All children must travel in a child seat, booster seat or booster cushion. Rule of thumb: if there's a safety belt, you must use it. It's the drivers' responsibility to be sure their passengers are using seat belts and appropriate child restraints.

The specifics:

For cars and goods vehicles (including MPV and SUVs): Children under 3 can only travel in cars or goods vehicles if there are fitted with the appropriate child restraint. Taxis are exempt from this rule. Children between ages 3 and 12 must use an appropriate child restraint in cars or goods vehicles if they are fitted with safety belts If the car or goods vehicle doesn't have safety belts, they must sit in the back seat. In passenger seats with an active airbag, rear-facing child restraints must not be used.

For buses:

Children between 3 and 12 must use safety belts if they are fitted If seatbelts are available, bus drivers are required to tell passengers that it is the law to wear them

The exemptions:
Taxis, hackneys and limousines do not need to have every kind of child restraints available A child over 3 can wear a seatbelt in the back seat of a car or a goods vehicle if there is no more room for a child safety seat If it is not possible to place your child in the back seat of your vehicle, they can ride in the passenger seat, as long as they are using the appropriate restraints. Child restraints come in several weight classes so you can find the appropriate one for your child.