Car seat laws in the UK are designed to keep your little one safe. Read about regulations on car safety, when children can use the front seat and more.
UK car seat laws state that you must use an appropriate child car seat when carrying children up to 135cm/4ft 5in or 12 years of age, whichever comes first (Gov.uk, no date). After that, they can use a normal seat belt.
Child car seats can be selected according to a child’s height or weight. But safety experts recommend that you use a child car seat for all children under 150cm. They also say that for children over 36kg (5st 10lb) but under 150cm, it’s best to go by height, not weight (Which?, 2022a).
What is an appropriate child car seat?
According to UK car seat law, an appropriate child car seat is one that:
- conforms to the EU-approved standards for weight or height
- is compatible with all the vehicles it will be used in. That means it is designed to work with a diagonal seat belt strap unless it is meant to be used with a lap seat belt, or with ISOFIX anchor points
- is suitable for the child's weight and size and is correctly fitted according to the manufacturer's instructions
- is not used in side-facing seats
- if it is fitted in the front passenger seat, that front airbag must be deactivited.
(Gov.uk, no date)
Generally, there are no exemptions for children with disabilities or medical conditions, unless a doctor issues an exemption certificate. But they can use a restraint designed for their needs (Gov.uk, no date).
i-Size seats are height-based seats. These seats need to face the back of the car until your child reaches 15 months old (Gov.uk, no date). In the UK, i-Size seats must be EU-approved and they will have a capital ‘E’ in a circle and ‘R129’ on their labels (Gov.uk, no date).
You can find out more about i-Size seats in this article (Which?, 2022b).
Weight-based seats must face the back of the car until your child is over 15 months old (Gov.uk, no date). In the UK, weight-based seats must be EU-approved and you will see a capital ‘E’ in a circle and ‘ECE R44’ on their labels. You choose the most appropriate seat by weight, and the weight ranges overlap.
You can see this article for more information about weight groups (Which?, 2022c).
Exceptions to car seat laws in the UK
If a car doesn't have a seat belt, children over three years old are allowed to travel in the back seat without sitting in a car seat. Children younger than three years old need to be in a car seat unless one of the following exemptions apply.
If the taxi does not have a child car seat, children under three can travel without a seat belt on the back seat. And children over three can travel in the back seat with a seat belt.
Unexpected but necessary journeys over a short distance
Where an appropriate child car seat is not available, a child over three years old can use the adult seat belt for an unexpected but necessary journey over a short distance. This doesn’t apply to a regular school run or planned journey.
You must not take children under three in a vehicle without a seat belt or the correct child car seat (except in the back seat of a taxi or minicab).
No room for a third child seat in the back
There might be no room for a third child seat in the back seat if two occupied child car seats in the rear prevent the fitting of a third child safety seat. In this case, a third child under the age of three can’t travel unless they are in the front seat with the correct child seat.
Children over three years old can sit in the back using an adult seat belt.
When can you use child booster seats?
Backless booster seats are now only approved for children taller than 125cm and weighing more than 22kg. This is group 3 in the weight-based system.
A smaller child isn't held as securely in the seat, the adult seat belt isn't guided across their body in the best way, and, most importantly, a booster seat offers no protection for a child if your car's involved in a side-impact crash.
You can still use booster cushions in the group 2 weight-based system if you already have them.
You can find out more about booster seats here (Which?, 2022d).
Penalties for ignoring the law
The consequences of ignoring the legal requirements for car seats could be expensive (at best) or fatal (at worst). Police are able to administer a fine of up to £500 if children are not in the correct car child seats (Which?, 2022).
Remember, it's the driver of the vehicle's responsibility to ensure all passengers are safely strapped in. If you're the driver, always check.
This page was last reviewed in June 2022.
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Gov.uk. (no date) Child car seats: the law. Available at: https://www.gov.uk/child-car-seats-the-rules (Accessed 8th June 2022)
Which? (2022a) Child car seat laws in the UK. Available at: https://www.which.co.uk/reviews/child-car-seats/article/child-car-seat-… (Accessed 8th June 2022)
Which? (2022b) i-Size child car seats explained. Available at: https://www.which.co.uk/reviews/child-car-seats/article/i-size-child-ca… (Accessed 8th June 2022)
Which? (2022c) Car seat weight groups explained. Available at: https://www.which.co.uk/reviews/child-car-seats/article/car-seat-weight… (Accessed 8th June 2022)
Which? (2022d) Car seats for older children, high back vs backless. Available at: https://www.which.co.uk/reviews/child-car-seats/article/booster-seats-a… (Accesssed 8th June 2022)