Discount clothing retailer Primark reported a 12% rise in total sales in the six months to February, while operating profits were boosted by 8% in the same period.

The steady growth figures were not able to prevent miserable half-year for owner Associated British Foods, which saw its pre-tax profits fall by half as a result of the collapse in sugar prices.

The strength of sterling against major currencies could have a negative impact on full year results, the company said, when combined with the weaker euro.

Primark is set to embark on an expansion programme in North America, with plans "well advanced" according to AB Foods chief exec George Weston. Its first store is expected to open its doors in the north-east US city of Boston this year.

AB Foods said the Primark sales rise was fuelled by an 11% increase in selling space at the chain, as the company opened a number of new stores across the globe.

If the new stores were discounted from the figures, then like-for-like sales were roughly level with the same period in the previous year.

Sales growth was restrained by "unseasonably warm weather across northern Europe last autumn and the impact that opening new stores in the Netherlands and Germany had on existing stores in the region," the company said.

Sugar slump hits AB Foods

AB Foods sugar business posted a £3m ($4.5m, €4.2m) operating loss, impacted by low sugar prices. The price of sugar in the European Union has fallen by around 40% in the past two years.

Its profits halved before tax to £213m, although the decline was offset by Primark's improved performance.

"As expected, profitability at AB Sugar was substantially lower as a result of much weaker EU sugar prices," said Weston.

"Primark's performance was driven by significant expansion of selling space and superior trading by the stores opened in the last 12 months and plans for its entry into the north-east of the US are well advanced."