Pret A Manger is stepping up its expansion plans in the US, even as the toughest recession in a generation has eroded its like-forlike sales by about 10%.

The company is increasing the number of store openings and expanding into Washington DC, and sees the US as a key driver of growth after UK profits have flattened out.

But its management team says there has been a sharp dip in sales in stores that have been open for more than a year, while growth has returned in the UK after a period of contraction last year.

'We are not entirely sure why sales in the US appear to be lagging the UK in terms of spending at our stores,' says Clive Schlee, chief executive. 'But we are determined to turn it round and we intend to do so.'

Financial Times