Next has blamed warmer weather towards the end of 2015 for a drop in sales in the run-up to Christmas.
In-store sales fell 0.5% between 24 October and 26 December, compared with last year. Online sales were up 2%, but its trading was described as difficult due to poor stock levels.
As a result, the fashion and homeware retailer said its full-year profits are likely to be at around £817 million - the lower end of its earlier £810-845m forecast.
The abnormally warm weather seen in November and milder temperatures seen in much of December meant that consumers were not buying winter clothing like coats and larger jumpers.
In addition to the impact of the weather, Next admitted that it made some "mistakes" during the period, "specifically, we believe that Next Directory's disappointing sales were compounded by poor stock availability from October onwards".