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Car Seat Law FAQs


If you’re a parent, you know how vital it is to have the correct car seat to protect your child in the event of an accident. Making an incorrect choice and getting caught with an unsuitable or incorrectly fitted booster seat could land you with a hefty £500 fine. To ensure your child is safely protected, read our guide to choosing the right car seat.

What is the law on child car seats?

• In the UK, a child must sit in a car seat until they are either 135cm tall or 12 years old, whichever comes first
• For kids over 135cm in height or older than 12, wearing a seatbelt like an adult is sufficient
• For children who do require a car seat, you can select which seat is appropriate based on their height or weight (more about car seat
categories below)
• Children MUST travel in rear-facing car seats until they are 15 months old
• Once your child reaches 15 months old, it should be safer to mount their car seat facing forward, as their neck will be stronger
• You must never fit a rear-facing child seat in the front of your car if there’s an active passenger airbag
• It is the driver’s responsibility to ensure that children under the age of 14 years are restrained correctly as per the law
• Since Feb 2017, manufacturers are no longer allowed to produce backless booster seats for children shorter than 125cm or weighing
less than 22kg – seats with backs are deemed safer as they offer improved side impact protection

Which car seat is legally required for my child?

It’s key to check that the seat you are buying is EU-approved for use in the UK – just look for a label with a capital “E” in a circle.

Furthermore, there are two categories of seats:

• Those that are manufactured to the latest EU standard ECE R129, known as i-Size and are based on a child’s height

• Those manufactured under the EU standard ECE R44-04, which are weight-based

Please note that only EU-approved car seats can be used in the UK.

What do I look for when buying a car seat?


There are various types of child car seats available, so take your time choosing the correct one. Visit shops and research online to get an idea as to what seats are available and which ones are most suitable for your child and your car.

It’s advisable taking your child and your vehicle with you when choosing a car seat and to find a reputable retailer who has trained employees to choose and fit the correct car seats. Even better, try to find a retailer who will help you try the seat in your vehicle before you buy it.

You can choose a car seat for your child based either on the child’s height or weight:

  • Height-based car seats are called i-Size seats
  • Weight-based car seats offer a range of options

- 0kg to 9kg or 13kg

- 9kg to 18kg

- 15kg to 36kg

Children weighing more than 22kg and taller than 125cm can use a backless booster seat.

Child seats must be fitted either using ISOFIX mountings or a diagonal seat belt strap.

For smaller children, a highback booster seat is recommended.

All i-size car seats come with ISOFIX fitting points. This means you can fit the car seat to your car safely without relying on seat-belts. ISOFIX fitting points are increasingly fitted to new cars as standard.

However, not all Isofix seats are approved for use in all Isofix cars, so check with the child seat manufacturer or retailer or the car manufacturer, to find out if your Isofix child seat is approved for your vehicle. Many have a list on their website that shows which seats are approved for which cars.


A quick guide to the correct size seat


Group Child's weight - applies to R44.04 seats Approx age of child

Child's height - applies to i-size seats

0 Birth - 10kg/22lb Birth to 6 - 9 months 40 - 85 cm
0+ Birth - 13kg/29lb Birth to 12 - 15 months 40 - 85 cm
0+ and 1 Birth - 18kg/40lb Birth to 4 years 40 - 105 cm
0+, 1, 2 and 3 Birth - 36kg/79lb Birth to 12 years 40 - 150 cm
1 9 - 18kg/20 - 40lb 9 months to 4 years 85 - 105 cm
1 and 2 9 - 25kg/20 - 55lb 9 months to 6 years 85 - 150 cm
2 15 - 25kg/33 - 55lb 4 to 6 years 105 - 150 cm
1, 2 and 3 9 - 36kg/20 - 79lb 9 months to 12 years 85 - 150 cm
2 and 3 15 - 36kg/33 - 79lb 4 to 12 years 105 - 150 cm

It's essential to bear in mind that moving babies and younger children up to the next seat up before they reach the maximum weight or height for their seat could lead to more severe injuries in a crash. Babies and children can vary wildly in size, so it’s much better to use height or weight as a guide for what car seat they should be in rather than age.


Is the child car seat suitable for my vehicle?

It is vital to check that the child seat you purchase will fit in your car and that it will fit in all the seat positions you intend to use it. The manufacturer and retailer should advise you.



Should I buy a second-hand car seat?

While it can certainly be much cheaper to buy a second-hand car seat, do proceed with caution.

The Royal Society for the Prevention of Accidents recommends that you avoid buying a second-hand car seat altogether, even from people you trust, as you don’t know if it’s been involved in an accident. You may not be intentionally misled by an unknown seller or a trusted friend, but minor damage can easily be forgotten or overlooked and still affect the safety of the car seat.

If you proceed with buying one second-hand, make sure you check the following before agreeing to a purchase:

• Examine it carefully for damage (do note that not all damage is visible to the human eye)
• Check that the seat has the ‘E’ mark and meets either the United Nations standard 44.04 or the i-Size standard (R129)
• Try the seat in your car – if you cannot fit it securely, do not buy it
• Make sure the seat is suitable for your child’s weight and height
• Check the manufacturer’s advice about how old the seat should be before it needs replacing
• Ensure the manufacturer’s instructions are available

When can children legally travel without a car seat?

In the UK, children must be restrained in a car seat until they are 12 years old or at least 135cm tall. From that point onwards they must use a seat belt like all adults.

Exceptions to this law include:

• A child can travel via taxi or mini-cab without a car seat if the driver doesn’t provide one. They must wear a seat belt
• Similar for coaches and minibuses. They must travel in the rear seats and use seat belts
• If you are making a short-distanced and unexpected journey, it is legally acceptable to restrain your child with just a seat belt instead of
a child car seat, providing your child is 3 years or older
• Children with special or additional needs or medical conditions will have bespoke requirements outside of normal laws. It is usual for
them to be restrained by means designed for their needs

What can I do if I need to get a taxi and I don’t have a car seat available?

If the taxi driver doesn’t provide the correct car seat, children are ok to travel without one, as long as they travel in the back seat.

• Child aged 3 or more must wear an adult seatbelt

• Can travel without a seatbelt if under 3

What happens if I break car seat laws?

Failure to ensure your child is in the correct car seat could result in you getting a £500 fine and the driver receiving up to 3 penalty points on
their licence. In turn, this could result in pushing up your car premiums as car insurers might perceive you as being a higher risk.

What if my car seat is stolen or damaged?

If you have been unfortunate enough to have had your car seat stolen or your vehicle has been involved in an accident, you might be able to can claim on your vehicle insurance policy.

Not all car insurance policies include this type of cover, even with fully comprehensive policies, so you might want to consider this when shopping around for cover.

Even insurers that do pay out for a claim don’t offer the same level of cover across the board, with as many as half of insurers only offering a full reimbursement.

What should I look for to ensure my car seat is properly installed?

If the seatbelt or harness is loose, twisted or appears to sit incorrectly across your child, make sure that you correct the placement before you head off. During the autumn and winter months, it’s best to remove your child’s bulky coat before adjusting the slack as the thickness of the material can leave the harness too loose to be effective in an accident.

Additional child car seat checks are:

• Is your child too small for the seat? If in any doubt, don’t move them to a larger seat until you’ve sought advice from a fitting expert
• If you’ve adjusted the seat’s headrest because your child has grown, ensure that the harness has been correctly routed back into place
• If you’re using a travel system seat with a carry handle, please remember to put it back to the correct position after putting your child in the seat
• If you’re using a seat that is suitable for a wide age range, do check it regularly for wear and tear, as it doesn’t necessarily stay safe for many years
• If you’re using a car seat with leg support, please check that the leg is fitted firmly to the car’s floor and that it’s at a 90-degree angle to the floor and not resting on an underfloor storage compartment – unless this has been filled with a car manufacturer-approved filler
• Do not secure a high-back booster with the car’s headrest – this needs to be moved out of the way to ensure the child seat sits flush with the car seatbelt
• If you’re using an Isofix seat, check that it’s properly clipped in. Indicators on the seat will change from red to green when it’s fitted correctly

Where can I get child seat fitting advice?


Any store that has trained child seat fitting staff can assist you. You could try Halfords, John Lewis, Mamas and Papas, or any number of independent retailers.  Perhaps avoid Argos as their staff cannot advise on the suitability of car seats or demonstrate how they should be fitted to your car.

You can also check Child Seat Safety's website who can provide you with a list of IOSH-accredited advisers on its website along with contact details to help help you find a local expert wherever you live in the UK.


How long should I leave my baby in a child car seat?

If you’re going to be travelling for a lengthy amount of time, it’s advisable to stop for regular breaks to allow you to check on your baby and change their position. Ideally, a second adult should travel in the back of the car with your baby, or if you are travelling alone it is helpful to secure a mirror to enable you to observe your child.

If at any point your child slumps forward, it’s recommended to stop and adjust their position.


Does my child require a rear-facing seat?

All children under the age of 15 months must be rear-facing because, before this age, their necks are not strong enough to withstand the pressure of a head-on collision in the forward-facing position. Groups 0 and 0+ are rear-facing.


Are there special car seat rules for babies?

Many infant car seats come as part of a wider travel system and can be clicked into the pram chassis with adapters.

However, expert advice states that car seats are for travelling alone and not intended for lengthy naps. The most ideal position for a sleeping infant is lying flat. It’s best not to keep babies in a car seat for any longer than two hours at any one time and they should be taken out frequently.



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