The FTSE 100 dropped 0.28 percent to 6,697.7 in London on Monday, while the FTSE 250 was 0.05 percent lower to 11,917.3.
The mining and oil sectors were lower in London.
Platinum miner Lonmin (LSE: LMI) dropped 6.85 percent to £39.85 for the worst performance of the session on the FTSE 100 after it issued a disappointing trading statement, saying that sales will be lower for the next year.
The announcement prompted a downgrade from Citigroup (NYSE: C).
Xstrata (LSE: XTA) was also lower, falling 1.78 percent to £33.61.
In the oil sector, Royal Dutch Shell’s (LSE: RDSA, RDSB; NYSE: RDS.A, RDS.B) A shares were 1.59 percent lower to £20.40.
BG Group (LSE: BG; NSYE: BG) was also lower, dropping 2.34 percent to 857p.
On the FTSE 250, Premier Oil (LSE: PMO) fell 2.57 percent to £11.75, while Burren Energy (LSE: BUR) was down 2.79 percent to 853.5p.
Back on the 100, SEGRO (LSE: SLOU), the rebrand of property development group Slough Estates, fell 2.04 percent to 599p.
Top gainers on the 100 covered several sectors, with bank Alliance & Leicester (LSE: AL) doing the best as it added 2.49 percent to £11.52.
Publisher Reed Elsevier (LSE: REL; Euronext: REN; NSYE: ENL; NYSE: RUK) was 1.66 percent higher to 675p, while in the pharmaceuticals sector, GlaxoSmithKline gained 1.63 percent to £13.10 on an upgrade from “underweight” to “neutral” from JP Morgan (NYSE: JPM; TYO: 8634).