There is still money to be made from the UK's woodlands and hedgerows, according to an economic botanist at Kew Gardens.

Dr Hew Predergast Predergast told the British Association science festival that nettles are a growing industry, with 2.5tonnes of the stinging weed being gathered each year to wrap around maturing cheeses. Similarly, wild elderflowers are the basis for a £10m industry, and the fungi market is said to be mushrooming.

'The more celebrity chefs we have on television, the more people will be wanting to do these things,' Predergast said.

He added that people are gathering wild fungi for use in expensive restaurants; they are picking fruit from blackthorn bushes to make sloe gin; and wildflower seeds are being harvested for sales in garden centres across the country.