The lingerie retailer invested in a new warehouse and replatforming its website in 2017.
Luxury department store posted a sales increase of 5% in the year to January 28.
A third of the sales are from lingerie and the firm has launched a luxurious new range with body positive model Ashley Alexiss.
The dramatic decline was largely due to exceptional charges related to warehouse and store closures.
The company said it is committed to its business plans and confident about the future.
The group posted a 42% rise in profits to £2.43 million for the UK and Ireland.
Accounts filed with Companies House reveal British lingerie business made a loss in latest financial year.
The department store chain was hit by rising costs and weakened customer demand.
Next said its prospects going forward appear “somewhat less challenging” than they did six months ago.
A strong performance from PrimaDonna swimwear and the introduction of PrimaDonna sportswear helped boost turnover.