Yorkshire Tea has angered some of its customers after it raised prices and slashed the number of teabags in one of its blends.

Its Decaf Bedtime Brew with Vanilla & Nutmeg has been reduced from 40 to 20 tea bags, but is being sold at a higher price at UK supermarkets.

At Sainsbury’s, the 50g box with 20 tea bags is retailed at £3, up from £2.50 for the 100g box.

Ocado is selling the tea bag blend for £3, up from £2, while Tesco is selling it for £2.99, up from £2.50.

The move has caused upset amongst some shoppers who now have to pay more for a box that is half the size.

Yorkshire Tea said it understood that the price rise “may not be welcome news”.

A spokesperson told : “We’re always looking for ways to keep our tea offering in step with changing consumer needs, tastes and trends.

“We’ve recently introduced two new ranges, bringing fresh choice to our customers while making some changes to our existing products.

“We know Bedtime Brew is much loved, and its move to our new fruit and herbal selection means we can keep offering this favourite.”

It added: “We appreciate that a price increase may not be welcome news, but it reflects the blend’s new place in the range.”

The decaffeinated black tea is made of lemon balm, lemongrass, nutmeg and vanilla.

Tea prices in the UK have risen in recent years, with farmers issuing warnings of short supplies as climate change hits their yields.

In August, tea prices were up 2.5 per cent, compared to 0.5 per cent in July.

Kenyan growers, who provide half of all black tea consumed across Britain, say unpredictable weather patterns and lower crop yields have driven up global tea costs.

Fintea, a union of tea farming cooperatives based in Kericho, said production across five of its cooperatives fell by 30 per cent in May and June this year.

Nelson Ngeno, the manager of Fintea, said farmers are “really scared” as their livelihoods are “cut short” by the changing conditions.

“Climate is really affecting our farmers,” Mr Ngeno said. “There has been a complete change as far as the weather is concerned.”