Asos issued a profit warning in the run-up to Christmas, sending shares down over 40%.

The online retailer said that sales had faced a “significant deterioration” and would continue to remain challenging.

The group’s sales growth forecast has been downgraded from 20 to 25% to 15%.

“Whilst trading in September and October was broadly in line with our expectations, November, a very material month for us from both a sales and cash margin perspective, was significantly behind expectations,” said Asos in an unscheduled announcement.

“The current backdrop of economic uncertainty across many of our major markets together with a weakening in consumer confidence has led to the weakest growth in online clothing sales in recent years. We have recalibrated our expectations for the current year accordingly.”

Chief executive Nick Beighton said: “We achieved 14% sales growth in a difficult market, but in the light of a significant downturn in November, we think it’s prudent to recalibrate our expectations for the full year.”

“We are taking all appropriate actions and our ambitions for Asos have not changed,” he added.

The online clothing retailer blamed the fall in sales on economic uncertainty and weaker consumer confidence.

The news comes amid difficult trading environments that have hit many high street stores. Last week, Sport’s Direct (LON: SPD) boss Mike Ashley said trading in November was “the worst on record, unbelievably bad”.

Whilst many brick-and-mortar stores have faced challenging retail environments, online retailers were considered to safe from the weaker consumer confidence and economic uncertainty.

The profit warning from Asos has sent shockwaves through the online retail industry, with shares in Boohoo (LON: BOO) falling over 10% and shares in Next falling 8% in morning trading.

Natalie Berg, who is a retail analyst at NBK Retail, said: “The last thing the sector needs right now is a profit warning from one of it’s few star performers a week before Christmas. E-commerce is often positioned as the death knell of the high street, so you know things are bad when even the online giants are struggling.”

Shares in Asos (LON: ASC) are currently trading down 40.43% at 2,498.36 (1019GMT).