Signet, owner of the H Samuel, Ernest Jones and Leslie Davis jewellery chains - and a big warehouse in Birmingham that has expanded to take on an extra 90 people over the past 12 months - ran up operating losses of £2.4 million in the UK during the six months to July in what it described as "very difficult" trading conditions.

That was more than offset by a bumper result in the US, which now accounts for 70 per cent of Signet's sales.

There, profits were 17.7 per cent ahead at £61.1 million on sales which rose by 10.8 per cent to £ 539.6 million, although the fall in the value of the dollar since the first half of last year clipped two per cent off profits.

In Britain, Signet's sales fell by 7 . 1 per cent to £183.3 million, or by 7.8 per cent on a like-for-like basis - reflecting setbacks of 8.4 per cent at H Samuel and 7.1 per cent at Ernest Jones.

In the same months last year there was a £6 million operating profit in the United Kingdom, including a £31.7 million restructuring charge.

Overall, Signet's profits were four per cent higher at £52.1 million on sales up six per cent - or 3.3 per cent likefor-like - at £722.9 million.

The interim dividend is raised by ten per cent to

0.4125p, in line with the pattern of the past three years. A similar increase in the final pay-out would give the shares a yield of 3.1 per cent at last night's price of 109p, unchanged on the day.

"The UK is still a good business," stressed Signet's chief executive, Terry Burman.

"Analysts are looking for a return on capital of over 30 per cent.

"There have been years like 2001 when the States was slow and the UK picked it up."

Mr Burman added that the outcome for the full year will, as usual, be influenced by the external trading environment on both sides of the Atlantic during the Christmas selling season.

"Our businesses will continue to execute their proven strategy and are well placed to compete," he said.

But in the United Kingdom, there are fewer shoppers on the high street and Mr Burman expects trading to remain difficult as the build-up to Christmas begins.

He doubts that Signet is faring worse than rival UK retailers and claims that it may be improving on its 17 per cent share of the jewellery market.

Positive signs include demand for diamonds which now accounted for 28 per cent of all sales against 20 per cent five years ago.

This meant that the average price of jewellery sold in the half-year rose by 4.6 per cent at Ernest Jones and by four per cent at the 380-plus H Samuel stores.