The child car seat wobbles dramatically as Peter Knowles, a road safety officer at Bromley council's road safety team, grabs it. If there were a crash, the little boy sitting in it would be thrown around.
We are in the car park of the Orpington branch of Sainsbury's, checking whether child car seats are fitted correctly. Last week The Observer revealed how two thirds of child car seats are not properly fitted, putting children at risk of injury or even death. Data collected by road safety officers around the country showed a litany of problems, from incorrectly routed seat belts to harnesses that are too high or loose.
Nor is the problem necessarily solved by buying a child car seat from a retailer offering a fitting service: consumer organisation Which? found that, in a mystery shop involving 43 stores, mistakes were made in nearly half of fittings.
At the Orpington Sainsbury's, parents are being offered a free car seat check. The mother with the wobbly seat says she was given it by a neighbour. "She showed me how to fit it," she says, as she opens the door of the family car to show us. "Not very well," says Knowles.
The seatbelt is twisted on the way in, and has been threaded in front of the tensioner, so it won't do its job, then back through both of the seatbelt guide clips, instead of just the one on the exit side. The occupant is just 10 months old and small for his age, and this is a forward-facing seat. Even properly installed, it won't offer as much protection as a rearward-facing one.
In a crash, facing backwards is much better as the child is thrown back into the seat rather than forward with the risk of whiplash. Knowles explains this and, as the boy's other seat is still at home, his mum promises to put him back in it.
Another woman is shopping with her third child. Her seat, a Maxi-Cosi Priori XP, is also fitted incorrectly. She says she knows how to do it properly but her husband has used it in his car and it hasn't been put back properly. Again the seatbelt is twisted and mis-routed, but this time so badly that later Peter says it "would have been no help whatsoever in a crash". The seat was bought from John Lewis, but by mail order so she has never been shown how to fit it properly. As Knowles explains how to tighten the seatbelt with the tensioner, she exclaims that she did not even know it was there.
These parents are not alone in making potentially dangerous errors: most apologise as their car door is opened and see straight away that the seat isn't fitted properly.
Various reasons, from husbands visiting the tip, to children undoing seatbelts, are given, but the problems seem to have the same origin. Parents are moving the seats regularly between two cars, are in a hurry as they do so, and do not really know how they should be fitted. By the end of the day around 60 have been checked, 30 have been refitted and six have been declared incompatible or condemned.
In the checks I watch there are several common mistakes that can be easily fixed. When it comes to group 0+ seats for the youngest babies, parents are putting the seats in the car with the handles in the wrong place. Many have the handle clipped back behind the child's head when in fact it should be up as it acts as a roll-bar in the event of an accident, and prevents the child from being pressed against the back seat.
Many of these seats are also too close to the front seats — a mistake I used to make with my own child. I believed that it would stop the seat moving and be a good thing in an accident, but actually it would have focussed the impact of the crash on one part of the seat. The seat should be around three fingers' width from the front.
When it came to group 1 seats, those for children weighing 9kg and over, most parents seemed to fit the belt through both of the seatbelt guides at the top, rather than just the one on the exit. This makes it hard to tighten the belt, and if the guide that it is incorrectly threaded through breaks in an accident, there would be a lot of slack in the belt and the seat could easily move.
Harnesses do not tend to be tight enough in either type of seat — you should be able to put just two fingers between the harness and the child, and parents seemed to be in a hurry to move their child to the next level of seating.
Knowles's colleague, Val Currie, tells me: "You should always keep your child in each seat for as long as you can, as they each offer more protection than the next one up." Only when a child is either too long/tall or too heavy for a seat, whichever comes first, do they need to move to the next one.
Most worrying are the parents who decline help. One we encounter clearly has a child in a rearward-facing seat, but has strapped the seat so the child is facing forward. With no powers to stop her, the road safety team have to let her drive off, even though the seat may not offer any protection.
JOIN OUR CAMPAIGN
The Observer is campaigning to highlight the problem of badly fitted car seats and encourage retailers and parents to ensure they are using seats properly. We want:
■ Retailers to ensure all their fitters are fully trained;
■ For retailers who sell online to offer fitting services in-store where appropriate, or offer parents details of where they can find local fitting services;
■ Better information for expectant parents on the importance of buying the right seat and fitting it correctly;
■ More manufacturers to provide "fit finder" services, like Britax. This shows which seats are compatible with their car.
One of the best ways to ensure your seat is properly fitted is to visit a clinic run by your local road safety team. We have teamed up with supermarket Morrisons and road safety officers to run seat-checking clinics at the following stores: West Kirby (4 October), Wigan WN2 (7 October) and Edinburgh EH5 (7 October). More dates will be confirmed shortly - go to theguardian.com/money for details.
Which? is offering readers a trial subscription for £1 allowing you to check out the results of its car seat tests. Call 0800 389 88 55, quoting WHICH54P, or visit which.co.uk
