You don't often meet a cheerful English farmer, but with the chalk hills of Surrey baking in the mini-heatwave like the Champagne region of France and his fruit hanging in heavy bunches on the vine, Chris White gives a fair impression of joy. Other farmers moan about milk prices, cold winters, trespassers, badgers and supermarkets, but White bubbles like the 400,000 bottles of fizz and other vintages he expects to make in November.

The prospect, says the manager of Denbies vineyard near Dorking, is for record sales and record quality. "2013 has been a quite perfect year so far with ideal conditions for growing grapes," he says. "It's been really stunning. We've seldom, maybe never, seen it like this before.

"The cold, hard snap got rid of the bugs; then in April, the critical time in vineyards, we had no frosts at all and when the vines flowered in June it was over in seven to 10 days. This year we expect, at a very worst case, to harvest 350 tonnes of the best grapes we have ever grown."

Britain now has 420 vineyards and around 100 wineries – nothing compared with France's 110,000 growers and 27,000 wineries – and Denbies, set up 25 years ago, is the largest of the lot. Its 300,000 vines produce around 10% of all the grapes grown.

"It's not just us. UK vineyards are on a roll," White says. "From being a doubtful grape-growing country only a few years ago, we are turning out to be a spectacular place to grow them. Our vintners are winning awards and demand now exceeds supply. We are even exporting it. We had a busload of French growers here the other week and they were dead impressed."

White puts the unlikely British success down to climate change and, in southern England, the chalk soils, which match those of Champagne and are perfect for sparkling wines. "Global warming is definitely happening. We know because we are getting fewer frosts, we have better harvests more frequently and we can now grow varieties of grape like carbernet sauvignon that we never could before.

"We are also harvesting earlier than we used to. We still see the droughts and have the cold snaps, but the temperatures are definitely improving."

But 2012, he says, was a disaster for nearly every British grape grower. Denbies harvested less than a quarter of what it expected, and other vineyards had to abandon whole crops in the wettest, coldest summer in 100 years. "It was once-in-a-lifetime bad. The fruit just did not set. We were due a good one this year."

Cultural attitudes towards English wine have changed in the last 20 years and more than four million bottles are now drunk each year. "The idea that it is expensive and poor quality is going out the window. You used to drink it to be patriotic but now there's wine for the connoisseur and Joe Public. It's being sold in Tesco and Sainsbury's. The jubilee and the Olympics helped, too.

"What has also changed is that all the vineyards are getting bigger. The average size 10 years ago was around 2.5 acres. Now it is eight or nine acres. They used to be trophy assets for rich people, but now you need about £1m just for an average-size vineyard. You need very deep pockets now because it takes four years or more before you can harvest the grape and land has become far more expensive.

"Round here, lots of farmers have seen the benefits and are turning a few acres to grape-growing. Some are linking up in the French way like a co-operative. But there is big money going in, too."

A £20m venture in East Sussex, financed by a former hedge fund operator, plans to produce more than 1m bottles a year by 2020. That would increase the amount on the market by 20% and turn it into a mass produced industry.

"I can see southern England turning into a major grape-growing region," says White. "All you need are deep pockets, a vision and nerve."