Britain's top shares index rose on Monday, as firmer mining stocks helped the market build on last week's recovery from a slump caused by Britain's decision to leave the European Union. The blue-chip FTSE 100 index, which had risen in the four previous sessions, was up 0.4 percent at 6,600.70 points in early session trading - its highest level since August 2015. Mining stocks were among the best performers, helped by a rise in London copper prices. The FTSE 100 fell around 6 percent and sterling tumbled against the dollar after the June 24 vote. However, sterling's weakness has provided a cushion to the FTSE 100 since many of the index's international companies can benefit from a weaker pound which would help exports.