Pupils as young as five used as "milkshake testers" by dairy giant

Müller is one of the country’s most recognisable milk brands and also sells yoghurts and orange juice.

The company is also responsible for milk products with added sugar, including flavours such as fudge brownie, choc orange, cookie dough, banana and strawberry.

Alison Johnstone MSP, the Scottish Greens’ health spokesperson, said: “This is a shocking use of children in school by a company trying to maximise its profits.”

A Royal College of Paediatrics and Child Health report recently revealed that 28 per cent of children in Scotland are overweight or obese.

Addressing the sugar content of food and drink has moved up the political agenda and the UK Government is pushing through a levy on the producers and importers of soft drinks.

However, attention has again turned to whether schools and councils are doing enough enough to promote healthy lifestyles in the classroom.

Earlier this year, company representatives visited Kilsyth primary, which has around 129 pupils, to test products that had a reduced sugar content. The sampling involved children from primaries one to seven and took place during the school day. Kilsyth primary was the only school used.

Each tasting session lasted about twenty minutes and the visit was agreed in advance by the council.

In a letter to parents ahead of the visit the local authority wrote: “We are planning to conduct a consumer study at your child’s school to understand children’s liking of some flavoured milkshakes. Participation in this study is completely voluntary.

“You or your child may decide to withdraw from this study at any time, and you may do so without penalty or loss of any benefits to which you are otherwise entitled.”

Kilsyth primary was earlier this year awarded £39,600 by the Scottish Government in Pupil Equity Funding, a pot targeted at children most affected by the attainment gap.

Johnstone said: “Parents across North Lanarkshire will be very concerned that school children have been taken out of their usual curriculum to be advertised to – and essentially used as milkshake testers – for a dairy company under the pretence of a campaign to reduce sugar intake.

“The best people to educate our children on the dangers of excessive sugar consumption are parents, teachers and healthcare professionals, not representatives from a company whose overarching objective is not health and wellbeing.”

Joanna Blythman, an award-winning investigative food journalist and author, said the test “reflects very badly on North Lanarkshire council”, adding: “Müller's milkshakes are sugar loaded so it's outrageous that the company was welcomed into a primary school. If Müller genuinely wants to test children's reaction to lower sugar shakes it can afford to pay for its own customer focus group testing outside school time.

"I suspect that 'product sampling' is just a crass 'foot in the door' attempt by Müller to market its sugary flavoured milks."

A spokesperson for Müller said: “Müller works closely with local authority teams in Scotland to reduce the amount of added sugar contained in flavoured milk served with school meals. We are proud of our milk products and happy to provide the children at Kilsyth Primary with a chance to take part in an interactive session on how they are developed. It is important to stress that the product tasting was entirely voluntary and of course, used only milk drinks which had already been fully tested and validated in advance.”

A council spokesperson said: "Pupils at Kilsyth Primary were asked to take part in a taste test as part of a drive to reduce the amount of sugar contained in flavoured milk served with school meals.

"No child was compelled to take part, they were asked to do so on a voluntary basis, and all parents were written to asking their permission. Not all children at the school took part in the tasting."