Marks & Spencer suffered a blow to its "Christmas spectacular" on Thursday after a glitch on its website left customers unable to place orders.

The High Street icon slashed 20% of prices on Thursday in a bid to lure Christmas shoppers into its stores.

But the retailer was left red-faced when, for several hours, customers who wanted to take advantage of the discounts online were unable to.

Nicholas Le Seelleur, Director Sitemorse™, comments; ‘The failure of the Marks and Spencer website demonstrates the critical importance of carrying out regular website testing and monitoring before launching a high profile promotion. It is vital to ensure that any potential faults and performance issues are identified and rectified well in advance – before costing the retailer valuable sales, damaging the brand's reputation and discouraging new online customers.’

In response, M&S has extended its 20% offer online until 1400 on Friday.

M&S blamed "unprecedented traffic to the website because of the Christmas spectacular" for the problems with ordering on the website.

"We apologise to any customers who experienced difficulties on Thursday," a spokeswoman for M&S said.

Guerrilla tactics

Thursday's one-day sale was the second M&S has staged in the run-up to Christmas.

High Street retailers have been resorting to savage price cuts amid increasing fears that shoppers are reining back spending this Christmas.

Rising mortgage rates and fears of a house market slump have made shoppers much more thrifty.

Several retailers have been adopting "guerrilla promotion" tactics, where prices are slashed at the very last minute before rivals have a chance to respond and compete.

M&S insists that the one-day spectaculars are not a panic measure, but merely a promotional tactic.

But analysts fear that M&S may be facing a massive stock overhang and that such severe price cuts will gnaw away at profit margins.