The group said profits would be “materially lower” than current market expectations for the year ending January 26 2019.
Chief executive Brian Brick said: “The beginning of the year has been hampered by short-term stock delivery issues caused by the consolidation of our supplier base.
“The resulting stock shortage has undoubtedly driven a significant shortfall in sales, which will continue until late spring. Although this has been a painful experience, I am confident that the availability issues are well on track to being resolved and the margin benefits from the consolidation will flow through.
“This stock shortage has led to a disappointing start to the year and whilst we are still at a very early stage of our new financial year, the more cautious consumer environment and the effect of short-term weather impacts has led to a readjustment of our profit expectations to protect the group’s longer-term investments.”