Confidence is all very well, but the Scottish Rugby Union yesterday admitted it had gone too far by marketing a T-shirt predicting a Calcutta Cup victory over England more than a week before Saturday's match with the Auld Enemy at Murrayfield.

The £15 shirt appeared on the SRU's online store late last week. Its wording, around the SRU's own copyright-protected thistle logo, proclaimed Scotland as Calcutta Cup winners. As it happens, Scotland's most recent victory was in 2008.

The presence of the shirt came to light in the wake of national coach Andy Robinson accusing the English team of arrogance at the recent Rugby World Cup. In that light, the fact the SRU should be selling anything predicting a win seems particularly ironic.

Members of the fans' organisation, the Federation of Scottish Rugby Supporters, were unsettled by its appearance. A spokesman said: "It seems like a remarkably stupid thing to do. Most of Scotland's great victories over England involved an element of surprise, catching an overconfident side on the hop, so it seems daft to fall into that trap. After our worst-ever performance at the World Cup last year, we don't really have many grounds for arrogance anyway."

Contacted by Herald Sport, a spokesman for the SRU at first admitted that he knew nothing about the item, but promised to investigate. A little later, he responded to say that the item had been removed from the SRU site – and it should never have been put there in the first place.

The fault, the Union spokesman said, lay with Greaves Sport, the Glasgow-based specialist retailer which took over the governing body's merchandising function a few years ago.

"Normally, these things are run past us before they go on the site," the Union spokesman said. "But this one wasn't. It seems it was the work of an overzealous marketing person at our retail partner in Glasgow. It was absolutely nothing to do with us."

A Greaves representative explained that the company had produced the shirts in 2008 and had put them back on sale last Friday.

"This was nothing more than administrative error with some old stock ending up on scottishrugbydirect.com by mistake," he said.

"These T-shirts were hugely popular in 2008 when Scotland last took Calcutta Cup honours and, hopefully, this will be a good omen for Saturday and they'll end up in demand once more.

" Everyone at Greaves wishes Andy and his team the best of luck in the big match."