Farmers across Europe are warning of a slump in food production and rising prices as crops from maize to salads suffer as a result of extreme heat, drought and wildfires.

Olive groves have also been hit as the climate crisis drives temperatures across the continent to fresh record highs, meaning the cost of olive oil – already at elevated levels – is expected to start rising again.

The vegetable growers association Légumes de France has warned that thousands of tonnes of products worth tens of millions of euros had been lost – including salad leaves, carrots, leeks, garlic and onion with production on certain crops expected to be halved because of the lack of rain.