Hedi Slimane has slammed a fashion critic as a ''schoolyard bully''.

The designer penned an open letter to Cathy Horyn in response to her scathing review of his debut Yves Saint Laurent show in Paris in which he also questioned her skills as a writer and ''challenging'' sense of style.

He wrote: ''Miss Horyn is a schoolyard bully and also a little bit of a stand-up comedian.

''Insiders argue she is an average writer, and a bit provincial, but I disagree, she did some great things. Her biggest achievement so far is a book about Bill Blass, that I haven't read. It might be terrific, and I'll be happy to recommend it, if it helps the sales.

''I also often hear that her sense of style is seriously challenged, providing that she is meant to be an authority in the village. This is totally irrelevant, no one has ever asked for her to be an inspiration to others after all, and likely it would never happen anyway.''

The writer - who hadn't been invited to the show following an on-going feud which stems from a piece she wrote in 2004 - had slammed the collection as ''lacking fashion spirit'', saying she ''expected more'' while praising ''terrific'' competitors Balenciaga, Dior, Givenchy, Celine, and Lanvin.

Despite the attack, in which Hedi also branded her a ''publicist in disguise'', Cathy insisted she isn't upset.

She told WWD: ''It's just silly nonsense to me.''