LONDON (Reuters) - Declines for Next (>> Next) and Standard Chartered (>> Standard Chartered) weighed on Britain's top share index on Wednesday, helping to offset a rally in commodities-exposed stocks.

Britain's blue chip FTSE 100 <.FTSE> ended 0.07 percent down at 7,487.96 points, while the mid-cap index <.FTMC> rose by 0.5 percent.

The FTSE gave up some gains after robust UK manufacturing data, which bolstered expectations for an interest rate increase from the Bank of England on Thursday and sent sterling higher.

A 9 percent plunge in Next's shares was among the main moves on the benchmark index after the clothing retailer said that trading was "extremely volatile".

Next's shares had gained about 38 percent since hitting a low in July but on Wednesday suffered their biggest one-day fall in 10 months.

Shares in fellow retailers Marks & Spencer (>> Marks & Spencer Group) and Primark-owner AB Foods (>> Associated British Foods) also fell, down 4.4 percent and 2.1 percent respectively.

"We're heading into Christmas and it's just a little bit hard to know what to expect from the retail sector given the volatility of the sales we've seen," said Jasper Lawler, head of research at London Capital Group.

"When inflation's going higher, the Bank of England's about to raise rates and consumer spending's falling off a cliff, all those things don't combine well for people selling on the high street."

Results also weighed on bank Standard Chartered, which sank more than 6 percent for its biggest one-day loss in almost a year after higher expenses overshadowed better than expected quarterly profit.

Miners helped to support the index, however, with Anglo American (>> Anglo American), Antofagasta (>> Antofagasta), BHP Billiton (>> BHP Billiton Plc) and Glencore (>> Glencore) among the biggest gainers, up between 1.6 and 3.4 percent after the price of copper jumped. [MET/L]

Outsourcer G4S (>> G4S) rose 1.1 percent after an upgrade from broker Jefferies, which raised its rating on the stock to "buy" from "hold".

"The shares have underperformed due to disappointing Q2 organic revenue growth but momentum should recover in H118E, driven by improving emerging markets and U.S. wage inflation," Jefferies analysts said in a note, referring to the first half of 2018.

Away from blue chips, mid-cap pharma company Indivior's (>> Indivior) shares jumped by 7 percent after the U.S. FDA backed approval for its opioid addiction drug.

(Reporting by Kit Rees; Editing by Keith Weir and David Goodman)

By Kit Rees and Danilo Masoni