US President Barack Obama and Republican challenger Mitt Romney were neck-and-neck in opinion polls in the final stretch before Tuesday's vote.

Some analysts say an Obama victory is perceived as negative for equities and a Romney win as stock-friendly.

Miners were the main drag on the blue chips, falling in tandem with weaker copper prices ahead of the US election, and after a private survey of China's growing services sector slipped in October.

Lower-than-expected new orders in the HSBC report injected a note of caution after three previous PMI surveys for October showed the world's biggest consumer of metals regaining momentum.

At 0805 GMT, the FTSE 100 index was down 33.70 points, or 0.6 percent at 5,834.85, having closed 0.1 percent firmer on Friday after a mixed US jobs report failed to give a clear picture of the health of the world's biggest economy.