More than eight in 10 drivers are putting children’s safety at risk by failing to correctly fit child car seats, according to a new study by What Car?.

A roadside investigation carried out by What Car?, in conjunction with Leicestershire Police and Child Seat Safety Ltd, found that only 15% of the child car seats assessed were fitted correctly and were appropriate to the children being carried in them.

Of 85 seats analysed at random, in 51 cars, only 31 (36%) were fitted correctly and, when the suitability and fitting of the child was taken into account, the figure dropped to just 13.

Three quarters (74%) of the incorrectly fitted seats inspected were able to be rectified on site but four seats – 5% of the sample – were condemned, with two being removed immediately and replaced before onward travel was permitted.

While car seats with ISOFIX attachments were all correctly installed, those that used the seatbelt as a restraint caused the most problems. The most common problem, accounting for a quarter (24%) of issues, was with the harness or seatbelt restraining the seat being too loose, twisted or incorrectly positioned.

More than one in six (16%) required the seatbelt to be re-routed and a further 11% needed adjustments to be made to the headrest to ensure optimum protection.

Up to the age of 12 years old, when it is assumed that children will be able to use the seatbelts fitted in a car, the driver is responsible for ensuring that an appropriate child restraint is fitted and that it is being used correctly.

Steve Huntingford, What Car? editor, said: “It’s clear that the overwhelming majority of drivers are aware of their responsibilities when carrying a child in the car. But, unless the child car seats have ISOFIX attachments, there is confusion over how to correctly fit them and ensure your child’s safety.

“At best, drivers could land themselves with a £100 Fixed Penalty Notice, but at worst they are significantly increasing the risk of death or serious injury to their children. It’s a form of Russian roulette that drivers are playing.

“We would urge anyone who transports children in car seats to seek professional advice about fitting them and buy their seats from specialists who offer free support not only at the time of purchase, but for the lifespan of the product.”

Mr Huntingford added: “Parents and carers often go to great lengths to ensure the safety of children in many aspects of daily life, and it is shocking that the proportion of unsafe child restraints in their cars was so high.”