(Open): Falling oil prices weighed on the London market as trading got under way for the week.
The FTSE 100 index was down 41.36 points, or 0.65%, at 6,302.39, with shares in oil companies among the biggest fallers.
Shares in BP dropped 2.4% and Royal Dutch Shell fell 3% after oil producers failed to agree an output freeze at their meeting at the weekend.
The price of Brent crude was down nearly $2, or 4.6%, at $41.13 a barrel.
Other commodity-related shares were also down, In the mining sector, Antofagasta fell 3.1% and Anglo American dropped 2.9%.
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