The FTSE 100 was down 24.74 points, or 0.4 percent, at 6,136.89 points at its close, outperforming the broader European market which extended losses after Wall Street fell.

Marks & Spencer rose 3 percent in strong volumes of 228.8 percent of its 90-day average, after it posted a decline in sales that was less severe than expected.

Traders took heart from new Chief Executive Steve Rowe's pledge to turn around its ailing clothing division, as well as continued strength in its better-performing food division.

"He is an executive that we are minded to back, one with the commitment, energy and insight to demonstrably take M&S on a better course, something for which long-standing shareholders pine," said Clive Black, head of research at Shore Capital, in a note, retaining a "buy" rating on the stock.

Supermarket Sainsbury also rose, up 2.7 percent after being upgraded to "outperform" from "underperform" by Credit Suisse, saying the food retail sector is a recovery story and that the grocer's bid for Argos owner Home Retail is "financially and strategically inspired".

Gold miner Randgold Resources was the top gainer on the index, rallying 3.2 percent after a target price hike by Credit Suisse and Dundee Capital. But JP Morgan's rating cut on Glencore and Antofagasta sent the shares down 5.7 percent and 2.6 percent respectively, with Glencore the top faller on the index.

Healthcare stocks were also in focus, with AstraZeneca up 1 percent, taking gains over the last two sessions to 5.5 percent and hitting its highest level since February earlier in the session.

Pharmaceuticals drew demand on Wednesday after Pfizer pulled out of a deal to buy Allergan, stoking rumours of fresh deal-making in the sector.

Fuelling demand for AstraZeneca on Thursday was an upgrade by Societe Generale, which lifted its target price and maintained a "buy" rating late on Wednesday.

Among the top fallers, Pearson was down 5 percent as it traded without entitlement to its latest dividend payout.

Investors also cited readacross from U.S. peer Apollo Education withdrawing its guidance overnight as weighing on Pearson's shares.

In all, stocks going ex-dividend on the FTSE 100 took around 13.5 points off the index.

Housebuilder Berkeley Group Holdings dropped 5.1 percent with traders citing a media report about a decline in London's luxury apartment market.

Worldpay also fell, down 2.9 percent to 274.7p after a top shareholder in the payment processor sold part of its stake for 269p.

(Editing by Ruth Pitchford)

By Kit Rees and Alistair Smout