Although it met its latest profit guidance, Next plunged 15 percent after warning that 2016 could be its toughest year since 2008, as it anticipated a more difficult economic environment.

"Their results were OK but their forward outlook isn't so great. Being a growth company that's highly leveraged as well, the minute it turns south, it turns south aggressively," Manoj Ladwa, head of trading at TJM Partners, said.

Next stock was set for its biggest daily loss since December 2008.

The FTSE 100 index was down 1.5 percent at 6,106.48 points by the close. The index fell 1.1 percent this week, posting its biggest weekly fall in six weeks.

Trade was quiet ahead of a four-day Easter weekend, with volumes at about three quarters of their 90-day average.

A fall in commodity-related stocks also put pressure on the blue-chip index, with the mining sector dropping 1.9 percent and the oil and gas index down 2.1 percent as the prices of metals and oil waned.

A rise in U.S. crude stockpiles to another record weighed on oil prices, threatening their recent rally. Brent crude dipped below $40 a barrel for the first time this week.

A higher dollar sent copper prices lower after a U.S. Federal Reserve official said on Wednesday the central bank should consider an interest rate hike as early as next month.

Schroders, Prudential and Sky all fell after going ex-dividend, taking around 5 points of the FTSE 100.

Among mid-caps, precision engineer Renishaw plummeted nearly 9 percent after cutting its full-year outlook, citing a lack of large orders from the Far East this year.

By Kit Rees and Alistair Smout