The Law
All children must travel in the car in an appropriate car seat until they are either 12 years old or 135cm tall
It is the driver's legal responsibility to ensure that all children under the age of 14 are correctly restrained in their car, even if the child's parents are passengers in the same car. For adults and children aged 14 and over it is their own responsibility to make sure they wear the seat belt.
Exceptions to the law
Babies and toddlers under the age of three must travel in an appropriate car seat in any private vehicle, whether it's your own or someone else's. The only exception for under-threes is that they can legally travel on an adult's lap in a taxi.
For children aged between three and 12 there are four exceptions to the law, which mean that in any of these four circumstances a child over three is legally permitted to travel in the car without a car seat.
These exceptions only exist for practical reasons, a child is never safe without a car seat, so you should try to avoid these situations whenever possible and make it a priority to use a car seat.
1. Travel in a taxi or minicab
It is not always possible to carry a car seat with you when you get a taxi. And as much as I would love to tell you never to get into a cab with your child, I know that sometimes you just don't have a choice. There are several belt fitted car seats available that are light enough to carry, so if at all possible try to use one of those. If you do travel in a taxi with young children and aren't able to use a car seat, then children aged three and over must use the adult seat belt, and babies and toddlers under three years old must be carried on your lap. You must wear the seat belt and hold the child in your arms, never put the seat belt around both of you.
2. When there are two occupied child seats in the car and a third won't fit
Some cars are wide enough for three car seats, but in a lot of cars when there are child seats fitted on the two outer seats, a third one simply won't fit in the middle. If you cannot fit three car seats in your car, you are allowed to put the biggest child in the middle with the adult seat belt. But only when all three children are in the car and the other two seats are being used. If you don't have all the children with you, then the child who normally travels without a car seat must use one of the empty seats, or one of them must be removed and replaced with one suitable for that child. A child must never sit in the back next to an empty car seat, no matter how short the journey.
3. When there are no seat belts fitted in the back of the car
Before the early to mid 1980's cars didn't have seat belts fitted in the back. If you own a very old car that doesn't have seat belts, your children are legally allowed to travel unrestrained in the back.
4. Short journeys of unexpected necessity in someone else's car
This exception to the law causes the most confusion and makes some people think that it's ok not to use a car seat in certain situations. I have come across several people without a car seat who say, 'Oh it's ok, it's not my car' or 'I only live around the corner, you don't need a car seat for short journeys'. They have misunderstood this exception.
ALL three points in this sentence must apply at the same time. It has to be a short journey AND it has to be in someone else's car AND it has to be of unexpected necessity, ie an emergency. A 20 mile trip to visit grandma in your sister's car is not a short journey. And getting a lift with a friend to go shopping is not an emergency.
The front passenger seat
Rear facing car seats can be used in the front seat, but only if the airbag is switched off or deactivated. For forward facing seats the rules vary from car to car, so please consult your car's manual if you want to use a forward facing car seat in the front seat.