At 0707 GMT, the FTSE 100 index was down 18.53 points at 5,757.18, or 0.3 percent, after closing 0.02 percent lower on Tuesday.

Miners led the modest retreat in London, weighed by a fall in the copper price, as investors looked for direction to Friday's meeting of central bankers at Jackson Hole, Wyoming, and any hints on further monetary easing.

Glencore was the top blue-chip faller, down 2.5 percent, having been the biggest FTSE 100 riser on Tuesday.

A Norwegian sovereign wealth fund has opposed the terms of commodities trader Glencore's proposed $30 billion takeover of miner Xstrata, the Financial Times reported on Wednesday, without citing sources.

Norway joins Qatar whose own sovereign wealth fund investment arm demanded improved terms and threatened to vote against the deal.