King Charles was accused of giving "a huge slap in the face" to the Buckingham Palace royal chefs - by enlisting French icon Raymond Blanc to help prepare this week's state banquet.

The monarch is said to have wanted to honour French president Emmanuel Macron by inviting Mr Blanc to assist the palace's own team in preparing food for the function. The first element of Mr Macron's state visit included the lavish meal at Windsor Castle's impressive St George's Hall, which Queen Camilla, the Prince and Princess of Wales and showbiz stars also attended.

But Darren McGrady, personal chef to the late Queen Elizabeth, Princess Diana and Princes William and Harry, said Charles' call to use Mr Blanc's support for the bash was unwise. He said: "I get that Raymond Blanc is one of the best chefs in the world, and I get that he is a King's Foundation ambassador, and I get that 'the collaboration is in the spirit of Entente Cordiale (a cordial agreement)' but it's a huge slap in the face to the palace royal chefs."

When Buckingham Palace announced Mr Blanc's involvement in the state banquet, a spokesman said he was invited to help "create the first course and dessert". He has a long friendship with the monarch and has been guest speaker at several royal events over the years, including horticulrural festivals at Highgrove.

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But it is understood while Mr Blanc, who runs Le Manoir aux Quat'Saisons in Oxfordshire, was asked to help with the main course, the celebrity cook left that part of the meal to Mark Flanagan, the Royal Household's head chef.

Yet, speaking to Mail Online, furious Mr McGrady, 63, added: "For sure, Macron will not be bringing in British chefs for a King Charles state visit to France." Mr McGrady, who worked as the personal chef to Princess Diana and her children until her death in 1997, hit back at the praise Charles has received for the move.

Some fans said it was a mark of respect to Mr Macron that King Charles called on Mr Blanc, born near Besançon, east France, to help with the culinary spectacular. It is believed dishes served on Tuesday had French inspiration or French twists.

Dad-of-two Mr Blanc, who has restaurants in central London, Portsmouth, Bath, Leeds and other British places, said he wanted to include the Royal Household's head chef as mark of respect to the monarch. He told Mail Online: "He's a royal chef who's cooked for the King for many years, plus he's a great friend – it's all part of respect.

"I could have done everything if I'd insisted, but Mark did a beautiful course – Rhug Estate chicken with British produce, with a beautiful tarragon sauce, a French way. It was a splendid occasion." Of McGrady's gripes, Mr Blanc added: "We all have an opinion – and I've got a different one. I like to bring people together."

Despite the criticism from Mr McGrady, King Charles also received a great deal of praise for inviting his friend Mr Blanc to help with the glitzy function at Windsor Castle. The Mirror has approached Buckingham Palace for comment.