Britain's top share index slipped lower on Monday, weighed down by a drop in major mining stocks which were impacted by a broker's downgrade on the sector, Reuters reported. The blue-chip FTSE 100 index fell 0.6 percent to 6,676.56 points in early session trading. The FTSE is up around 1.5 percent since the start of 2015 but is some 6 percent below an April record high of 7,122.74 points. Miners, which account for around a tenth of the FTSE 100 in terms of market capitalisation, dominated the index's list of worst-performing stocks, with Anglo American falling 2.6 percent while BHP Billiton declined 2.4 percent.