Catering manageress Marion Jones rejected reservations about pupils’ ability to cope, and now says: “I was right - my cherubs are handling the system fine. It’s the adults who can’t handle it. Kids are very adaptable.”

The system, which is also being piloted in three local secondaries at a total cost of Pounds 60,000, is straightforward: Parents send a cheque or give their children coins to clock up credit on their cards at revaluation machines - known by the children as “revving up” at the rev machines. This means the cafeteria service is cashless and therefore much quicker.

Another benefit is that if parents are able to pay by cheque it cuts out the need for children to use cash at all. Money for meals is therefore less likely to get lost, be extracted by a bully or diverted to buy sweets or comics.

The child’s photograph on the card offers extra security, discouraging theft. And if the card is lost, any money on it can easily be transferred to a new card.The chances of losing the card are slim, however, since after it is swiped in the cafeteria, Bothwell administrative staff take custody of it until the following day, rather than returning it to the child.

A major advantage of the system is that children from low-income families who receive free meals up to the value of Pounds 1.16 cannot be identified by the cards. Mrs Jones says she has no problem with poor take-up of free meals, but in secondary schools up to half of those entitled do not take them, largely because of the stigma attached. Some primary children take a packed lunch rather than accept a free ticket.

A surge of 15 per cent to around 170 meals a day in this 400-pupil school in Uddingston confirms that the conversion to plastic has been a positive experience. Take-up by P1s was particularly marked.

Mrs Jones attributes the success to an advance presentation on the new payment system and the meals themselves. Children and parents were invited in for a talk and an opportunity to try out the cafeteria for themselves.

Around five parents a week at Bothwell take up the option of a computer print-out of what their child has been eating, either because of the child’s medical condition or because of a general interest in the child’s diet. The cards can even be programmed not to accept certain foods.

Mrs Jones feels she already goes some way to satisfying parents’ desire that children eat healthily. She has banned chips, serving mashed or baked potatoes instead. Headteacher Mohraig Gwyn-Davies gives her stamp of approval to the scheme, designed by CRB of Edinburgh, which is likely to be extended to the rest of South Lanarkshire either through leasing or purchase: “Staff have all applauded it,” she says. “We are serving in a shorter length of time. We’re not taking coins which kids drop on the floor. It is very smooth.

“The kids think it is fun and feel very grown up. We’re teaching them skills for life. In the real world everyone has a card.”

Mrs Jones concludes: “If there is a drawback, it is coping with the extra demand for meals. But I wouldn’t go back to the old way.”