We all know fashion is a fickle thing - but for Marks & Spencer, this adage is particularly true.

Once upon a time, back in the early 90s, dear old Marks and Sparks was loved by everyone.

The hoi polloi could aspire to buy its clothes, the elite would happily condescend to patronise it - even Margaret Thatcher declared her loyalty to the store's underwear.

We loved the tights and skirts and suits, the seemingly luxurious food, the tempting gift section - and M&S clocked up profits that, at its height, topped £1bn a year.

Then, in the late 90s, the chain suddenly became unfashionable and customers abandoned it in droves.

The blouses seemed dowdy, the suits passe and an air of gloom descended on the aisles.

In those dark days, it was hard to find anyone with an ounce of fashion nous who would even admit to browsing in M&S, never mind buying anything.

But now the store appears to be back in vogue.

It is celebrating a surge in sales netted during the all-important Christmas period and the chairman and chief executive Luc Vandevelde has cheerfully announced customers are "clearly coming back and buying more".

Figures show overall sales rose by 8.3 per cent in the seven weeks to Saturday, January 12.

Food sales rose by 5.4 per cent, while clothing, footwear, gifts and home goods shot ahead by 10.4 per cent.

The store that once refused to accept credit cards or stock any brand except its own appears to have sharpened up its ideas of late.

Last September saw the arrival of the first Per Una collection, targeted at the young and fashion-conscious and designed by George Davies, of Asda and Next fame.

The arrangement with Davies was a major break with M&S tradition. Davies insisted his products should be sold on non-M&S hangers, fitted in specifically-designed changing rooms and taken away in non-M&S carrier bags.

There were those who doubted whether Davies could really work his magic in this store but his range has gone down well with the public.

Then M&S made a bold decision to start selling spring clothes in January. This move guaranteed the store acres of press coverage and made it appear well ahead of the game.

So, has the company got its sparkle back at long last, or are its new sales figures just a flash in the pan before a return to gloom?

Richard Perks, senior analyst at Retail Intelligence, says it's too early to say.

"This is the first really promising news we have had out of the company since things went pear-shaped around the autumn of 97," he said.

"But it is only a first step and we've got to see if it can sustain this and move forward."

Perks believes the main challenge facing M&S is the market place, which has changed since the store's boom days in the early 90s.

"Consumers have become a bit more demanding over the past few years and they look for greater fashionability, better clothes make-up and quality of design," he said.

"And if they just want the basics, as often as not, they are prepared to go and shop at places that are lower priced, like George at Asda."

Perks contends M&S lost its way because it pushed too hard for profits in the mid-90s.

"I think they probably did that, whether intentionally or not I don't know, by compromising on the quality of merchandise. And I think consumers eventually just voted with their feet - they didn't buy any more.

"The M&S brand should stand for quality and value for money and that's what they've got to get back."

Richard Hyman, chairman of the retail research company Verdict, believes many customers who avoided the store for a few years are now returning, while those who continued to make the odd purchase are now buying more.

This, he argues, is because the store is adapting to market changes and a greater demand for individuality.

"A retailer like M&S has to sell clothing to pretty much everybody because it's a big business," he said.

"The main problem is people no longer want to buy en bloc.

"Women of today no longer want to shop from the same racks as their daughters and their mothers."

"The only way to respond to that is to make them feel there are little pockets of ranges that have been put together just for them."

Thus customers entering a remodelled M&S today would find several specialist ranges - from the young Per Una collection, to the designer Autograph section and an area focusing on classics to suit slightly older customers.

By following this strategy, Hymen believes the store is making good progress, even though it has "a long way to go".

But, he also points out that M&S has been unfairly treated in some ways.

"In the last couple of years, I bet you couldn't find anyone who would admit to buying anything at M&S - and not only that, people said they never had," he said.

"But it's amazing how fashion dictates how people talk and think about things.

"It wasn't possible for M&S to have the high sales they did and for people not to be buying from them."