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Child car seat laws in the UK

Car seat laws in the UK are designed to keep your little ones 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 restraining system (child car seat) when carrying all children up to 135cm/4ft 5in or 12 years of age, whichever comes first. 

However, safety experts recommend you use a child car seat for all children under 150cm.

For those over 36kg (5st 10lb) but under 150cm, it’s best to go by height, not weight.

What is an appropriate child restraint?

According to car seat law, an appropriate child restraint is one that:

  • conforms to the United Nations standard, ECE Regulation 44/03 or ECE 44/04 (this is marked on a label on the seat). It's worth knowing that a new European standard for child car seats - the i-Size standard - will eventually come into force and replace the R44.04 standard (read more below).
  • is compatible with all vehicles it will be used in,
  • is suitable for the child's weight and size and is correctly fitted according to the manufacturer's instructions.

There are a number of exceptions to the law.

Exceptions to car seat laws in the UK

In taxis

Children under three can travel without a child car seat or seat belt on the back seat.

Children over three can travel using an adult 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

If there’s no room for a third child seat in the back seat (where two occupied child car seats in the rear prevent the fitting of a third child safety seat) 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 can either use the front seat with the correct child seat or sit in the back using an adult belt.

What is the i-Size standard?

The i-Size is the new European standard for child car seats. i-Size seats will fit every i-Size approved vehicle and cars will need to be i-Size compliant to achieve the maximum Euro NCAP rating.

The i-Size regulations are designed to provide children with additional protection and safety in the car. For now, i-Size does not replace the existing R44/04 legislation, but eventually it will become the only standard. 

The key differences are increased support for a child's head and neck, and better protection in the event of both frontal and side-impact. The seat's five-point harness ensures that a child stays in the seat even in a roll-over accident.

New booster seat law

Under rules that are came into force in February 2017, backless booster seats will only be approved for use for children taller than 125cm and weighing more than 22kg.

Previously, children weighing as little as 15kg, that's around three years old, could travel in backless booster seats. But many child car seat experts agree that this type of booster seat is unsuitable for such young children.

A small child isn't held as securely in the seat, the adult seat belt isn't guided across their little 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.

The change doesn’t affect existing models of seats or cushions and doesn’t mean that they are unsafe or illegal - though parents are still being encouraged to make sure they know the rules for using child car seats. The change to the technical standards means that the range of products available on the market are better suited for younger children.

Find out more here. 

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 an on-the-spot fine of £30, or £500 if the case is referred to court.

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 article was written using information provided by Which?

Page last updated: April 2017

Further information

NCT’s helpline offers practical and emotional support in all areas of pregnancy, birth and early parenthood: 0300 330 0700.

Make friends with other parents-to-be and new parents in your local area for support and friendship by seeing what NCT activities are happening nearby.

Good Egg Safety has a complete guide to your child’s in-car safety

Good Egg Safety host or support car seat checking events across the UK every year. Find one near you

Find out more about the i-Size standard.

Read more about why you need to use a child car seat

Find out more about keeping babies safe in the car

Find out about Kids in the Car - a campaign encouraging parents to be aware of the impact their driving behaviour has on even the youngest children.