Companies should be wary of alienating loyal customers by tampering with tried-and-trusted brands, says a report from market research company Datamonitor.

The report warns manufacturers of long-established products that ’brand loyalty’ may be more important than attracting new consumers.

"It costs nine times more to attract a new consumer than retain an existing one," said the report.

It added that many brands are evocative of childhood memories - and consumers attribute symbolic meanings to brands across many consumer goods.

According to a survey last year by the Grocery Manufacturers Association in the US, only 29% of brand-loyal consumers would buy an alternative product, if their favourite brand was out of stock in a particular shop. Most would prefer to go to another store or wait until their next shopping trip to see if their chosen product was back on the shelves.

Consumer market analyst Matthew Adams, author of the study, said that while customers were often on the look-out for new goods, they liked to be sure long-established favourites, such as Hovis, were still around.

Earlier this year, Allied Bakeries put £14m behind a TV advertising campaign to re-launch Kingsmill after the company admitted the flagship brand had lost its way with the poorly-received advertising campaign ’The King’.

The pull of brand loyalty was demonstrated by Warburtons hanging onto its position as number one bread brand last year, helped by achieving nationwide distribution.