Photo: Maxim Hopman / Unsplash. Illustrative photograph.
In Great Britain, children must use a child car seat until they are 12 years old or 135 cm tall, whichever comes first, and the driver is legally responsible for every passenger under 14. Adults aged 14 and over are responsible for wearing their own seat belt. This guide is for learner and new drivers in England, Scotland and Wales who will soon be carrying younger brothers, sisters or friends’ children. It explains Highway Code Rules 99 to 102, the seat types allowed, the exceptions and the fines.
Key facts
- You MUST wear a seat belt in a car, van or other goods vehicle if one is fitted (Rule 99).
- Children need a child car seat until 12 years old or 135 cm tall, whichever comes first.
- The driver is responsible for passengers under 14. Passengers 14 and over are responsible for themselves.
- Only seats labelled with the E in a circle and R129 (height-based) or ECE R44 (weight-based) can be used in the UK.
- Never fit a rear-facing baby seat in a seat protected by an active frontal airbag (Rule 101).
- The fine is up to £500 for not wearing a seat belt, or for carrying a child under 14 without the correct seat or belt (as of November 2026).
Who is responsible for wearing a seat belt?
The Highway Code sets out who is legally responsible in a table under Rule 99. Here it is in plain terms:
| Who | Front seat | Rear seat | Who is responsible |
|---|---|---|---|
| Driver | Seat belt must be worn if fitted | Not applicable | Driver |
| Child under 3 | Correct child restraint must be used | Correct child restraint must be used. In a taxi without one, the child may travel unrestrained in the rear | Driver |
| Child from 3rd birthday until 135 cm tall or 12th birthday (whichever first) | Correct child restraint must be used | Correct child restraint must be used where seat belts are fitted (see the exceptions below) | Driver |
| Child over 135 cm, or aged 12 or 13 | Seat belt must be worn if available | Seat belt must be worn if available | Driver |
| Adult passenger aged 14 and over | Seat belt must be worn if available | Seat belt must be worn if available | Passenger |
GOV.UK also says only one person is allowed in each seat fitted with a seat belt. Two children sharing one belt is not allowed.
Which child car seat does a child need?
GOV.UK describes two types of approved seat. Check the label before you buy or borrow one.
Height-based seats (R129)
These seats are chosen by the child’s height. The child must be rear-facing until they are over 15 months old. After that they can face forward. Check the seat label to make sure it suits your child’s height.
Weight-based seats (ECE R44)
| Group | Child’s weight | Seat types |
|---|---|---|
| 0 | Up to 10 kg | Lie-flat or lateral baby carrier, rear-facing baby carrier, or rear-facing baby seat with harness |
| 0+ | Up to 13 kg | Rear-facing baby carrier or rear-facing baby seat with harness |
| 1 | 9 to 18 kg | Rear or forward-facing seat with harness or safety shield |
| 2 | 15 to 25 kg | Rear or forward-facing high-backed booster seat or booster cushion, with seat belt, harness or safety shield |
| 3 | 22 to 36 kg | Rear or forward-facing high-backed booster seat or booster cushion, with seat belt, harness or safety shield |
The weight ranges overlap, so more than one seat type can suit a child. Manufacturers can now only make new booster cushions approved for Group 3, but existing Group 2 cushions can still be used.
How to fit a child seat legally
- Use the seat only with a diagonal seat belt strap, unless it is designed for a lap belt or fitted using ISOFIX anchor points.
- Fit it exactly as the manufacturer’s instructions say (Rule 100).
- Never put a rear-facing baby seat in a front seat with an active frontal airbag. Deactivate the airbag first (Rule 101 and GOV.UK).
- Do not fit a child seat in a side-facing seat.
- Put bags and shopping in the boot, with heavy items low down. Anything loose on a seat or parcel shelf can hit someone under hard braking, and Rule 98 says any load MUST be secure.
- Let children get in and out through the door nearest the kerb, and use child safety door locks where fitted (Rule 102).
Rule 102 also advises not to let children sit behind the rear seats in an estate car or hatchback unless a special child seat has been fitted.
When can a child travel without a car seat?
GOV.UK lists a small number of exceptions:
| Situation | Under 3 | 3 and over |
|---|---|---|
| Taxi or minicab without a suitable seat | May travel without a seat or belt, but only in the rear | Must wear an adult seat belt, in the rear |
| Unexpected, necessary, short journey and the correct seat is not available | Only allowed in a licensed taxi or minicab, in the rear | May use an adult seat belt |
| Two occupied child seats in the back stop a third being fitted | Must travel in the front in the correct child seat | May sit in the back using an adult belt |
| Rear seat has no seat belt fitted | Not covered: under 3s must be in a child car seat | May travel in the back without a seat or belt |
Read these exceptions narrowly. The “unexpected, necessary, short” case needs all three: a planned school run does not become unexpected just because fetching the right seat is a hassle. The taxi exception covers licensed taxis and minicabs only, not a lift in a friend’s or relative’s car. If you are not sure an exception applies, get the correct seat or change the plan.
Vans follow the same rules as cars. Coaches and minibuses have their own rules, and Rule 99 says passengers aged 14 and over in minibuses, buses and coaches must wear a seat belt where one is fitted.
Exemptions for adults
Rule 99 lists two exemptions: holders of a medical exemption certificate, and people making deliveries or collections in goods vehicles when travelling less than 50 metres. For a child who cannot use a restraint or belt because of a medical condition, a doctor can issue an exemption certificate. Children with disabilities otherwise follow the same rules, and may use a disabled person’s seat belt or a restraint designed for their needs.
Fines
- Up to £500 if you do not wear a seat belt when you are required to.
- Up to £500 if you are driving and a child under 14 is not in the correct car seat or wearing a seat belt.
Annex 8 of the Highway Code, the safety code for new drivers, asks you to make sure everyone in the car wears a seat belt throughout the journey. With friends in the car, say it before you set off. See carrying passengers for the first time.
Scenario: the school run with three children
You have passed your test and are asked to drive your 2-year-old cousin, your 7-year-old sister (125 cm) and her 13-year-old friend.
- 2-year-old: must be in the correct child seat for their weight or height. You are responsible.
- 7-year-old at 125 cm: under 12 and under 135 cm, so needs a child seat or booster. You are responsible.
- 13-year-old: must wear a seat belt. You are still responsible because they are under 14.
- If the two child seats in the back leave no room for a third, the under 3 would have to go in the front in the correct seat, with the front airbag deactivated if the seat is rear-facing.
Common questions
What age can a child stop using a car seat in the UK?
At 12 years old or 135 cm tall, whichever comes first. After that they must wear a seat belt.
Can a child sit in the front seat?
The Highway Code table sets the same requirement for front and rear seats: the correct child restraint for the child’s age and height, or a seat belt once they are 12 or 135 cm. A rear-facing baby seat must never go in front of an active frontal airbag.
Who gets fined if a 15-year-old passenger is not wearing a belt?
Passengers aged 14 and over are responsible for wearing their own belt, so the passenger would be liable. For passengers under 14, it is the driver.
Do I need a car seat in a taxi?
Not if the taxi driver does not provide one. Children must sit in the back: under 3s may travel without a seat or belt, and children aged 3 and over must wear an adult belt.
Can I use an old Group 2 booster cushion?
Yes. New booster cushions can only be made as Group 3, but existing Group 2 cushions can still be used.
What is the fine for not wearing a seat belt?
Up to £500 (as of November 2026).
Back to the main guide: Learning to Drive in Great Britain. Related: before you drive checks and the theory topic safety and your vehicle.
Sources
- Department for Transport, “The Highway Code: Rules for drivers and motorcyclists (89 to 102)” (gov.uk)
- GOV.UK, “Child car seats: the law” (gov.uk)
- GOV.UK, “Child car seats: when a child can travel without a car seat” (gov.uk)
- GOV.UK, “Seat belts: the law” (gov.uk)
- Department for Transport, “The Highway Code: Annex 8. Safety code for new drivers” (gov.uk)