TESCO announced its first steps into the US yesterday with plans for a £250m-a-year expansion of its Express store format.

The long-awaited move across the Atlantic will see the UK market leader open its first convenience stores on the West Coast next year.

Chief executive Sir Terry Leahy said the move was tremendously exciting.

He said: "It is a market we have researched extensively for many years and, over the past year, we have committed serious resources to developing a format that we believe will be really popular with American consumers."

Tesco said it planned to develop the US business through organic growth, rather than by acquisitions.

The venture is designed for the US market and is modelled on the company's Express format, which operates in five countries, with more than 800 stores.

The operation will be run by Tim Mason, who joined Tesco in March 1982 and is the company's marketing and property director.