London-based Clay O'Shea alleges the shirts with Cockney slogans are copies of his own, which he has been selling since summer under the label Slang, and says that logos including "Bristols" and "Trouble and Strife" can be seen in both collections.

According to reports, friends of O'Shea, a fitness trainer whose clients include Mel B formerly of the Spice Girls, say that O'Shea's father always used to speak in rhyming slang. The Slang t-shirts have been selling at London's Harvey Nichols and The Cross for around $58 all summer and have been seen on celebrities including former All Saints singer Melanie Blatt and Lisa Stansfield. They've also been featured in I.D. and Nova magazines.

In a statement, O'Shea said: "The Slang label has been in stores for almost six months. Stella McCartney is clearly a talented designer, so frankly I was surprised to see the slogans on the runway for next season. I will be seeking legal advice."

A spokesperson for McCartney denied O'Shea's accusations, saying that she is unaware of O'Shea and doesn't know "anything about his clothes." He explained that McCartney has been thinking of using Cockney slang and slogans "for some time."