Waitrose, the supermarket, saw sales of organic chickens rise by 31pc in the second week of January, the week the programme aired, while free range chickens from its Select Farm range rose by 24pc. Overall poultry sales at the chain rose by 7pc over the week in question, the highest weekly sales figure of the year outside of Christmas or Easter.

Asda and J Sainsbury also reported increases in sales. "Sales of organic chickens have gone up but so have Basics, our value line," said a Sainsbury's spokeswoman.

A source close to one large supermarket said that sales of free range and organic poultry had risen eightfold since the programme aired.

The TV show, Jamie's Fowl Dinners, featured scenes showing battery-farmed chickens being slaughtered. The show attracted controversy for its content and for comments that Oliver reportedly made criticising Sainsbury's, whose ad campaign he fronts, for not sending a representative to a televised debate. Oliver later wrote an open letter to Sainsbury's staff apologising for his outburst.