German-owned discount retailer Aldi has reported a 210 per cent increase in annual operating profits to £43.88 million (€65.43 million) in the vehicle that runs its Irish and British stores.

Aldi is considered to rank among the most efficient supermarket chains, but new filings for the chain indicate that its business turns a lower operating profit margin than the acknowledged sector leader Tesco.

The Irish-registered vehicle Aldi Stores (Ireland) Ltd does not file separate accounts for the chain's 36 stores here but it is believed to be highly profitable.

Newly filed figures for its British-registered immediate parent Aldi Stores Ltd indicate that the significant rise in profits at more than 300 British stores and the Irish stores was recorded against the backdrop of only a modest gain in sales last year.

With turnover at the stores climbing to £1.13 billion from £1.02 billion in the 12 months to December 2005, operating profits rose to £43.88 million from £20.88 million.

This implies an operating profit margin of roughly 3.89 per cent, lower than the 5.78 per cent that Tesco reported in the year to February 2006.

Tesco enjoys considerable advantages of scale: its total sales last year were greater than £39 billion.

Aldi will open its 37th Irish outlet in New Ross, Co Wexford, this week, bringing the supermarket group a step closer to the 40-store threshold that was indicated as its medium-term ambition when entering the market in 1999.

The chain and its German-owned rival Lidl have made rapid inroads in the booming Irish market through organic growth.

The most recent figures from researchers TNS Worldpanel Ireland indicate that their combined share of the grocery market reached 6.7 per cent in the 12 weeks to September 10th, a new record.

Lidl had 4.2 per cent of the market, while Aldi had 2.5 per cent, these figures say.