One of Britain's retail grandees has hit out at sustained regulatory investigations into the nation's grocery sector, describing the latest probe into price-fixing as "outrageous and irresponsible".

In a rare interview, Lord Sainsbury of Preston Candover accused the competition authorities of being over-zealous in their approach to supermarkets.

"I feel that they do not recognise it is an incredibly competitive industry," he said.

Scandalous

"It is a waste of time and energy and I think that it is scandalous that this is in the public arena. If this [probe] comes to nothing, they are being punished by the publicity when there is no proof," he added

Lord Sainsbury's comments come after an unusual burst of regulatory activity around the sector. In the past 10 days, the Big Four chains - Tesco, Asda, J Sainsbury and Wm Morrison - have been visited by the Office of Fair Trading (OFT) looking for evidence on alleged price-fixing across a whole basket of goods from bread to toothpaste.

The supermarkets were also accused by the watchdog of price-fixing in the £10-billion-a-year tobacco market within 24 hours of the co-ordinated visits.

But as the OFT plugs away on alleged price-fixing, its sister body the Competition Commission has given the sector a clean bill of health.

Unveiling the findings of a two-year investigation into the £120-billion-a-year grocery market last week, the regulator said it had found no evidence of direct or indirect collusion between supermarkets on prices.

Lord Sainsbury, who led Sainsbury for 23 years and remains a shareholder in the supermarket chain, said that retailers had endured enough scrutiny, having gone through three competition enquiries in the past eight years.

"In such a vast industry you might be able to find some episode in which [price-fixing] could happen, but overall the consumer is well served and the companies involved are not making excessive margins."

Archie Norman, the former Conservative MP and Asda chief executive, has also hit out at the regulator for devoting such a large amount of its energies to a market which he says is highly competitive. Richard Brasher, Tesco's commercial and trading director, said last week that he found the continual scrutiny "wearying and disappointing". "We do our best for customers," he said.

The latest probe by the OFT is broader in scope than any over the past decade, with consumer goods makers also being brought into the investigation.

Procter & Gamble was visited at its UK offices in Weybridge, while a host of other global names - Coca Cola Enterprises, Mars, Unilever, Nestle, Kimberley Clark - have also been sent letters requesting information on their dealings with Britain's biggest companies.

- Financial Times