The Duke of Edinburgh Prince Philip has questioned the benefits of organic farming, despite his son HRH Prince Charles backing the methods through his Duchy Originals brand.

Speaking to ITV, he said: “Organic farming is not an absolute certainty that it's quite as useful as it sounds. You have got to be emotionally committed to it - but if you stand back and be open minded about it, it is quite difficult to really find where it has a real benefit.”

Organic systems at Highgrove were met with “complete ridicule” 20 years ago he added: “It's interesting now that it isn't ridiculed to the same degree. I think people are beginning to realise that some of the chickens are coming home to roost and settle heavily in the genetically modified trees.”