Shares in Next fell 9.1% in Wednesday trade after the fashion retailer issued a cautious trading update.
Next said third-quarter trading had been "extremely volatile", adding that this volatility made it hard to determine any underlying sales trend.
Online sales growth at Next's Directory business continued to offset falling sales on the High Street, with sales up 1.3% overall in the quarter.
Overall, the benchmark FTSE 100 index fell 5.12 points to close at 7,487.96.
Shares in rival retailers were also hit by Next's update, with M&S down 4.5%.
Primark owner Associated British Foods dropped 2.1%, while Debenhams fell 4%.
Away from the retail sector, shares in Standard Chartered bank dropped 6% after its third quarter revenue growth of 4% fell short of expectations.
Paddy Power Betfair was the biggest riser in the index, climbing 4.5%, after it reported higher third-quarter revenues and made a small increase to its full-year earnings forecast.
Revenues in the three months to 30 September rose 9% to £440m, and it now expects underlying earnings to be between £450m and £465m.
On the currency markets, the pound was 0.16% down against the dollar at $1.3262, but was 0.05% higher against the euro at €1.1411.