Marks & Spencer will tomorrow hold a one-day 20 per cent off sale amid further signs of anxiety over the downturn in consumer spending.
The retailer will slash prices in its fashion and homewares departments in its biggest one-day promotion for four years.
M&S will join other big name high street retailers discounting their stock this week, including Debenhams and Bhs.
It came as a leading firm of stockbrokers made a further cut to its profits forecast for the retailer. Seymour Pierce stockbrokers downgraded its 2008/9 estimate from £650m to £630m, but left the following year's forecast unchanged at £535m.
Analyst Freddie George said the M&S sale was a "clear sign that sales are well behind budget" as it enters the festive season.
He said consumers appear to be delaying their Christmas shopping, hoping to catch bargains as shops increase their sales.
"Christmas 2008 has the feel of being the worst retailing Christmas for many years - more for the higher level of discount activity," he said.
M&S executive chairman Sir Stuart Rose has not attempted such a large one-day sale since his "Christmas Spectacular" just after he took over in 2004.
A source today said the earlier sale was "for very different reasons".
"If you look down the high street [now], there's just loads of discounting going on out there."
M&S has recently struggled as shoppers snub its premium end food offering, while its clothing is also being squeezed by competition at both ends of the market.
General merchandise - including clothing - saw like-for-like sales fall 6.4 per cent in the 13 weeks to 27 September although Sir Stuart has said M&S continued to offer "quality, stylish product" and was confident about its autumn and winter ranges.
The retail bellwether's overall UK like-for-like sales fell 6.1 per cent - its worst quarterly performance since January-April 2005.
Yesterday the company announced that George Davies, the fashion designer behind its hit Per Una womenswear range, would leave at the end of the year.