Under current UK law, all children travelling in a car must use the correct car seat until they are 12 years old or 135cm tall.
Under the new rules, backless booster seats will only be approved for use by children taller than 125cm and weighing more than 22kg.
At the moment, children weighing as little as 15kg, around three years old, can travel in backless booster seats.
But child car seat experts from consumer organisation Which? say that this type of booster seat is unsuitable for such young children.
They say a small 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.
A backless booster seat, also known as a booster cushion, currently satisfies the legal car seats law requirement for children up to 135cm tall, and they’re cheaper, but are not recommended, especially for younger children.
Which? child car seat expert, Lisa Galliers, said: “A decent high-backed booster seat provides better protection in a front crash, as they’re designed to guide the adult seat-belt across the child’s body properly, and our crash tests prove they offer much more protection in a side-impact crash than a backless booster seat alone.”
The new additions to the child car seats regulations should come into effect in December 2016, but will only apply to any new products appearing on the market.
So parents buying a booster seat next year should start to see that they are not approved for use with children under 125cm and 22kg.
Parents who have a booster seat now will still be able to use the seat without breaking any rules.