Shares in the clothing company N Brown have tumbled after it warned of “subdued” trading in recent weeks.

The company behind the brands JD Williams, Simply Be and Jacamo fell 13.5% to 273p a share following the warning.

The shares were also dented by a fall in pre-tax profit for the last financial year, and a warning that the UK fashion industry was faced with “challenging conditions”.

Angela Spindler, the company’s chief executive, said the retailer was midway through its transformation from a catalogue business to an online retailer, and benefits were already being felt, particularly in the second half of the year to 27 February.

She added: “Looking forward, whilst we face challenging market conditions for the fashion sector overall, and trading since the year end has been subdued, we remain confident in our ability to make further progress this year.

“This is based on the strong appeal of our specialist fit proposition, continuous improvement in the customer experience and changes in customer shopping behaviour, driven by targeted marketing.”

Based in Manchester, the company, which counts the former cricketer Andrew Flintoff and television presenter Lorraine Kelly among its models, said annual pre-tax profits had fallen 7.8% to £72.2m.

The company said the fall in pre-tax profit reflected exceptional costs of £17.2m, mainly taken in the first half of the year and associated with the closure of its clearance stores, reorganisation costs and VAT-related legal and professional fees.

The board left the final dividend unchanged at 14.23p a share.

Revenue rose 3.5% to £866.2m. Over the year, 66% of all traffic was from mobile devices as N Brown progressed its bid to become a “digital-first” business.

Darren Shirley, analyst at Shore Capital, said the results for the last financial year were in line with expectations, but downgraded expectations for full-year profits in 2017 following the company’s cautionary statement.

Shirley added: “The British consumer is showing signs of more caution in recent weeks and months reflected in the plateauing of consumer confidence and cautionary comments from captains of the apparel world including [Next chief executive] Lord Wolfson and [Marks and Spencer chief executive] Steve Rowe.”

Analysts at Peel Hunt downgraded their forecasts for N Brown, adding they had “little confidence that the business will show meaningful traction”.