SHARES in JD Sports plunged more than 20% this morning after the “athleisure” retailer issued a profit warning, following a Christmas period that fell short of expectations.

The trainers specialist told the City that growth of clothing revenue had been impacted by milder than anticipated weather from the start of September. It said trading conditions had been “softer and more promotional” over the peak period than expected, denting margins.

Revenue grew by 6% on a constant currency basis over the 22 weeks to December 30, with like-for-like sales up 1.8%, which the retailer said was “slightly behind our expectations”

The company said it now expects full-year organic revenue growth of around 8%, and anticipates that full-year gross margin rate will be slightly lower than last year, as it revised down its expectations for profit before tax to between £915 million and £935m.

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Steve Clayton, head of equity funds at Hargreaves Lansdown, said: “JD Sports, the self-proclaimed King of Trainers is looking rather dethroned this morning after issuing an unplanned trading statement. JD says that sales have grown by less than expected as pricing in its markets became more promotional.

“Margins have suffered as a result and analysts are lopping about 10% off their current year forecasts and seem likely to take at least as much off their projections for beyond this year. The shares tumbled by 20% in early trading.

“It’s not all bad news from the high street though. Next has issued an upbeat trading statement, citing better than expected sales both in-store and online.”

Régis Schultz, chief executive of JD Sports Fashion, said: “We have made good progress against our five-year strategic plan, delivering global organic revenue growth of 6% in the period, against very tough comparisons with last year, and opening over 200 new JD stores in the year.

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“Our key markets have seen increased promotional activity during the peak trading season, driven by a more cautious consumer, but we continue to grow market share. We are confident in our strategy, and we continue to invest in our supply chain, systems, and stores, supported by our strong cash generation and healthy balance sheet.”

Shares in JD Sports closed the day down 23% at 119.7p.