Jamie Oliver could have irrevocably soured his relationship with Sainsbury's by criticising parents who buy junk food, experts have warned.

Oliver criticises parents in his new C4 show, Jamie's Return to School Dinners, saying: "Now is the time to say 'if you're giving your young children fizzy drinks you're an arsehole, you're a tosser. If you give them crisps you're an idiot."

But analysts warned that his contract to front the retailer's campaign could be at risk after chief executive Justin King criticised the comments. King wrote in The Guardian: "His attack is neither correct nor the best way to achieve change. Dictating to people - or unleashing an expletive-filled tirade - is not the way to get engagement."

One analyst said: "It will undoubtedly have affected the relationship as he is trying to dictate to Sainsbury's.

"The language he used deserved the response that it got."