Mugged. Done over. Ripped off. And furious.

That's how one angry supplier feels after what he claims has been the unfair treatment meted out to him by one of the UK's leading multiple grocers.

The remarks are made in an anonymous submission to the Competition Commission's inquiry into the UK's grocery market. But to which supermarket chain is he referring?

It will come as a surprise to many to learn the source of his indignation is not one of the usual suspects - Tesco, Sainsbury's or Asda.

Instead, it is Waitrose, the retailer that prides itself on its ethical trading practices and fair treatment of suppliers. This is not a side of the chain the correspondent, who titles his letter to the Commission 'Mugged by a multiple' and signs off as 'Anon', recognises.

He alleges that after approaching Waitrose with a new product range, the retailer went on to market a similar line soon afterwards without his involvement.

"I am of the distinct opinion that I have been done over by a supermarket," he writes. "The supermarket in question is Waitrose. I am furious that they ripped off my recipes (making sure they were different enough not to have any legal challenge from me).

"My main gripe is that after a very promising start with them, to which I will bring emails and correspondence as proof, they went completely cold on me, non-responsive, and lo and behold six months later they have listed a series of speciality butters that stink of my innovation and development. Worse of all they never offered me a fair due process of tender or presentation."

Later in the letter, he asks the Commission to arrange a "face-to-face with a senior manager of Waitrose/John Lewis, just so I can ask them honestly why I was not allowed to compete and succeed on a level playing field with a product that takes up less shelf space and is head and shoulders above the concept and packaging they have gleaned from my own hard work".

A Waitrose spokeswoman said: "Our buyers receive hundreds of enquiries andproducts from prospective suppliers on a daily basis and on many occasions there are inevitably similarities between ideas based on current food trends."