The Co-operative Group has launched a range of cereal bars made with oats grown on its own farms.

The products join a growing list of lines, including peas, pumpkin and onions, that have been repackaged and branded with the retailer's strapline 'Grown by us, Britain's largest farmer'.

But the fruit in the bars comes from further afield and includes pear from China, apple from Chile and raisins from Turkey.

"We could have made up to 90% of the bar from products we grow in the UK," said Christine Tacon, general manager of Co-op Farms. But the cost of using our fruit and segmenting production at the manufacturer would have been huge and the product would have sold at a premium."

Even the cost of using Co-op malted wheat flakes would have been too high because of the small amount needed, she added.

The Co-op won't put its farms' message on a product unless it is at least 25%-grown by Co-op farmers. For single-ingredient products, that proportion rises to 50%.