English wine producers are watching the skies with bated breath as they hope for an excellent vintage despite the wettest summer for decades.

Although rain has fallen – in some cases torrentially – throughout most of August, the key months of May and June were dry and cloudless, and an Indian summer is being predicted for September, with temperatures in the mid-20s and clear sunny days.

‘If the weather stays like this for the next four to five weeks,’ Frazer Thompson of award-winning vineyard Chapel Down said, ‘it will be a very good harvest.’

While crops like wheat and corn have been flattened by winds and ruined by rain, vines have blossomed.

‘May and June are vital months for flowering and fruit set, and people forget how nice they were,’ Thompson said, ‘and September is also critical. If we don’t get any frost the Pinot Blanc and the Pinot Noir for the sparkling wines are going to be sensational.’

Producers are expecting high yields, as vines put out more fruit shoots after a very hot summer like 2003, and the rains of August have filled out the grapes.

The grapes should have lower sugar levels than in 2003 but better acidity – hence the optimism for the sparkling wines.

But Thompson warned there are still five weeks to go before harvest in early October – during which time one serious frost could ruin everything. ‘I have no curtains in my bedroom – deliberately, so I can watch the weather all the time.’

Written by Adam Lechmere