English winemakers are reporting “catastrophic” crop damage after the worst frost in a generation wiped out at least half of this year’s grape harvest.

Chris White, the chief executive of Denbies Wine Estate in Surrey, said up to 75% of its crop was damaged by last week’s sub-zero temperatures: “The temperature dropped to -6C and at that level it causes catastrophic damage to buds,” he said.

White said staff had worked in vain using special fans and heaters to protect the vineyard, which at 265 acres in the UK’s biggest, after an Arctic blast swept across the UK. “We are very disappointed and it’s quite heartbreaking for the people who work in the vineyard all year round,” he said. “From what I hear the majority of English vineyards have been affected to some degree.”

Some of France’s most famous winemaking regions, including Champagne, Bordeaux and Burgundy, were also affected by last week’s severe frosts. The bad weather is expected to mean another poor year for French producers after last year’s cocktail of hail, frost and mildew resulted in one of the smallest harvests in 30 years.

The blow dealt to this year’s wine harvest is a setback for an industry enjoying huge success, with Denbies, Nyetimber and Ridgeview among the South Downs vintners winning international acclaim for sparkling – and increasingly still – wine produced in an area that has a geology and microclimate similar to Champagne. It also comes after four record years, a strong run that has encouraged the industry to plan a record 1m vines over the next 12 months.

The number of acres planted with grapevines in England and Wales has already more than doubled to about 5,000 acres over the past 10 years with two big French champagne houses, Taittinger and Vranken-Pommery Monopole, among those investing in English wine projects.

Chris Foss, head of the wine department at Plumpton College in East Sussex, said he had contacted vineyard owners around the south-east to gauge the bad weather’s impact on this year’s harvest and while some crops were unscathed others had been “decimated” with 90% of buds destroyed. One grower described it as the “worst frost since 1997”.

“I’ve been in English wine for 30 years and never seen anything like it,” said Foss. “It looks like there will be a 50% drop in this year’s expected yield – if not higher.” The length of the winemaking process means the supply squeeze will not become apparent to wine drinkers until 2018 when this year’s still wines are released and 2020 for sparkling wine.

Nick Wenman, who owns the Albury organic vineyard in Surrey, said the devastating cold snap had been the biggest setback he had faced since planting the vineyard eight years ago. Despite lighting 500 candles and burners to warm the air, 80% of its vines were damaged by the freezing temperatures.

“It’s been a stark reminder of the difficulties faced by wine producers in the country, and yes … at this moment we are asking ourselves whether we were mad to try and grow vines in England,” said Wenman who is trying to look on the bright side. “Some buds have escaped altogether and the damaged vines should develop secondary buds … whilst these may not be as fruitful or have as much time to ripen, they give us hope for a harvest this year.”