The UK’s parched wheat fields are entering a ’critical’ phase, with yields already down 10-15% and more dry weather on the way.

Crops in the south and east of the country are under stress, with ears forming two weeks earlier than normal after less than half the normal levels of rain in March and the hottest April on record.

The dry weather has continued in May, with above-average temperatures predicted until the end of the month, prompting environment secretary Caroline Spelman to call an emergency ’drought summit’ of water companies and farming groups earlier this week.

Wheat in France, Germany, Eastern Europe and the US is also suffering from unusually dry weather, while heavy rain has delayed plantings of Canadian wheat. All this is underpinning high wheat and flour prices, with the delivered price of a tonne of wheat standing at around £220.

"Concern is growing by the day and the markets are getting jumpy. We are now losing yield as every dry day and week goes by," said Jack Watts, senior analyst at the Home Grown Cereals Authority. He estimated that yields in the UK could be down by between 10-25% on last year.

At miller Rank Hovis, head of wheat procurement Gary Sharkey said: "Given current weather patterns, yields could be down 10-15% on last year, which is a big concern. Farmers are currently unwilling to forward-sell, because they are not sure they will have the quantity or quality to meet orders. The next few weeks are critical. A couple of inches of rain in early June would help salvage the situation."

Earlier this month, the US Department of Agriculture forecast that global wheat production for 2011/12 would be 669.5mt and consumption at 670.5mt.

“The wheat market supply and demand is finely balanced and any production shortfall could lead to a tighter supply situation,” said ADM Milling in a statement. “The lack of rainfall has caused some in the industry to question the likely yield potential of this crop, with some traders in the UK estimating up to a 10% reduction in the UK crop size.”