The blue-chip FTSE 100 index <.FTSE> ended up 0.4 percent at 6,297.20 points. The index is down around 4 percent since the start of 2015, and nearly 12 percent below a record high reached in April after concerns about a slowdown in China, the world's second-biggest economy, knocked back global stock markets.

Credit data company Experian was among the top FTSE 100 performers, rising 2.3 percent after a price target upgrade from broker Citigroup. The stock had already surged on Tuesday following strong results from the company.

"Experian's results are better than expected, indicating resilience in many of its business lines and geographies," said Gary Paulin, co-founder of brokerage Aviate Global.

SABMiller also progressed 1.9 percent after AB InBev launched its $100 billion-plus (65.75 billion pound-plus) takeover bid on Wednesday and agreed to sell SABMiller's 58 percent stake in U.S. joint venture MillerCoors.

Supermarket operator Sainsbury slid 7.1 percent after reporting a drop in first-half profits and announcing plans to cut more prices to close the gap on fast-growing discounters Aldi and Lidl.

"Despite all the positive talk about strategy delivery, Sainsbury continues to lose sales and market share and reduce margins thereby reducing return on capital. Sainsbury expects the tough background to be maintained through the second half so respite is still some way off," said David Stoddart, analyst at Edison Investment Research.

Telecoms provider Talktalk, which is in the FTSE 250 mid-cap index, <.FTMC> jumped 13.2 percent.

TalkTalk's shares slumped in October after the company fell victim to a cyber attack, but the stock recovered on Wednesday after TalkTalk raised its interim dividend by 15 percent and maintained its guidance for this financial year.

(Additional reporting by Kit Rees; Editing by Catherine Evans)

By Sudip Kar-Gupta