FTSE 100 dragged down by mining stocks

(Close): London's leading shares dipped in Tuesday afternoon trading to close in negative territory, with mining stocks leading the downward trend.

Mining firms weighed on the market as the price of copper dropped to a 10-week low. Antofagasta shares fell 5.5% while Rio Tinto slid 4.7%.

The FTSE 100 index closed down 17.26 points or 0.25% at 6,820.79.

Primark owner Associated British Foods was the biggest riser on the index, gaining 3.4%.

The firm notched up gains after analysts at RBC increased its rating on the stock to "outperform" from "sector perform".

Shares in business supplies firm Bunzl fell 0.3% despite a 6% rise in the company's half-year profits to £155.6m.

Bunzl said it was "difficult to give a firm view" on the impact of the Brexit vote, but added it did not expect a significant impact on its business.

On the currency markets, the pound fell 0.15% against the dollar to $1.3087 and was up 0.24% against the euro at €1.1741.