Drinks firm Diageo have teamed up with Irwins baking group to develop the bread, which has now been launched in more than 250 Tesco supermarkets across Ireland and the UK.

The European licensing director of Diageo, David Berry, said the move was the first step in what the company hoped would be a very fruitful relationship between Guinness and the retail food market.

"We have been keen for some time to harness the qualities and taste of Guinness into suitable food products for the commercial retail market, " said Berry.

"Bread was a natural starting point for us, and we hope [it] will pave the way for further massmarket foodproduct development for us."

Produced at Irwin's Portadown bakery in Co Armagh, Guinness Whole Grain Bread is a wheaten loaf made with 17% real Guinness, although the alcohol content evaporates during baking.

According to Gráinne Macken, head of corporate communications for Diageo Ireland, there has already been considerable interest in the product internationally.

"We've had calls from all across Europe and even farther afield, " she said. "We were pleasantly surprised with the enthusiasm for the bread."

Macken said Diageo's move into other products would probably focus on those foods that have already been proven to work well with Guinness.

"We'll be looking at things like Guinness stew, Guinness pie and condiments and sauces such as Guinness mustard, " she said.

"We'll also be looking at a range of other breads.

Obviously, there are some things that Guinness just won't go well with, so we won't be expanding into all foods."

Macken denied that the move into food was a reaction from Diageo to slipping sales of Guinness over the past couple of years.

The firm sold 8% less Guinness in Ireland in the year to 30 June 2006 compared to the year before and sales were also down 3% in the UK.