Parents and teachers may dismiss worries about the weight of books carried by schoolchildren as whingeing, but they may be storing up problems for the future. Back pain accounted for 117 million days off sick in 1996-7, according to DSS figures.

“If you come to school wearing a bag over two shoulders, you get called a square,” says Thomas, aged 15. Thomas, who weighs 10 stone, often carries almost two stone to school, most of it in a briefcase which drags down one arm.

“It’s only cool to wear a rucksack over one shoulder,” agrees 13-year-old Robert, who used to regularly carry up to one stone until his school introduced lockers recently.

It is often the oldest children at primary school and the youngest at secondary school who shoulder the biggest burdens. They are not seen as needing so many books as GCSE or A-level exam students, yet with fewer organisational skills and many subjects each day, they may need to tote a large bundle around. With reports of children as young as 10 carrying 20 per cent of their weight over one arm, it is not surprising that the National Back Pain Association (NBPA) has called for children to limit the load they carry to 10 per cent of their body weight.

There are no regulations governing the health and safety of children carrying loads, whereas adults at work are not supposed to carry more than 20 per cent of their body weight for more than 10 minutes without a break. The NBPA found that 44 per cent of children walked an average of 25 minutes to school each day. They carried textbooks and writing equipment for the day, as well as sports kit, musical instruments and technology materials.

A recent court case in France claimed that one 12-year-old girl was carrying 40 per cent of her weight to school each day. Her father wanted this to be declared illegal. He failed in his case, but a debate was sparked off in the French media. In Britain, parents and children have been slow to object to pupils’ burdens, but there are signs that this is changing. Lockers have been mushrooming in schools, but a recent survey showed that 40 per cent of schools do not provide any.

Constraints on space deter many schools from providing lockers - plus the tendency for children to lose keys. Although most manufacturers provide master keys and can supply spares for the individual cupboards. Charles Kitchin at WB Bawn amp; Co, makers of top-selling Helmsman steel lockers, says the trend is towards either swivel locks which can be fastened by the pupil’s own padlock, or coin-return locks, with individuals taking a locker for a particular period of time. Such options are particularly suitable for sports and theatrical facilities also used by the wider community. Full compartment lockers cost around pound;17 each; a coin-operated system suitable for wet areas costs pound;45.

The aesthetics of storage space mean that lockers are often consigned to corridors. In turn, concerns about fire-risks often lead to schools opting for metal models. Yet there are several furniture makers who produce attractive oak or beech veneered cupboards, with either barrel or hasp and padlock fastenings. Interform, for example, also offers lockable library units and several sizes of locker, suitable for books, sports or music storage. Prices range from pound;138 for a bank of three small wooden lockers.

Neither the of two biggest teaching unions, the NUT and the NASUWT, have official policies on the weights children carry to school. An NUT spokesperson said: “What children carry is a matter for them and how individual schools organise themselves is up to them.”

Perhaps PE teachers could explain to pupils that even if it is “uncool” to wear a rucksack properly, it would be worse to grow up with curvature of the spine.

* Interform Contract Furniture, 8 West Hampstead Mews, London NW6 3BB. Tel: 0171 328 2340.

* WB Bawn amp; Co, Northern Way, Bury St Edmunds, Suffolk IP32 6NH. Tel: 01284 752812.

* National Back Pain Association, 16 Elmtree Road, Teddington, Middx TW11 8ST. Tel: 0181 977 5474. Send an SAE for an information pack