The FTSE 100 inched 0.2pc lower by 0710 GMT, lagging most of the global markets where signs of progress in the US-China trade talks lifted sentiments. The FTSE 250 midcap was seen up 0.3pc.

Vale SA said it has been authorized to partially resume dry processing operations at the complex, months after Brazil's mining regulatory agency had ordered the miner to halt operations there to guarantee the stability of its dams.

Rio Tinto was the biggest drag with a 3.3pc drop, while Anglo American and BHP were also lower, as Liberum analysts flagged warning signs for the sector after rising iron ore port inventories.

Helping contain losses was broadcaster ITV, which jumped 7.2pc after it said a strong contribution to online revenue from reality show "Love Island" helped limit the decline in first-half ad revenue.

Among midcaps, Aston Martin slumped 22pc after it slashed several of its forecasts, blaming macro-economic uncertainty and weakness in UK and European markets. That followed a disappointing quarterly update from its German peer Daimler.