Update: Oil stocks have dragged the FTSE 100 into the red as the price of Brent crude dipped ahead of a crucial meeting of the Opec cartel of oil-producing nations on Thursday.
The price of a barrel of Brent crude dipped 0.7% to $63.42, while US West Texas Intermediate oil was down 1.7% at $57.95.
That follows a strong rally for the oil price, up 11.7% since the start of October.
'West Texas Intermediate and Brent crude oil are in the red today after having a positive run recently ahead of the Opec meeting on Thursday,' said David Madden, market analyst at CMC Markets UK.
'There is speculation that major oil producers will extend the oil production cut until the end of 2018. Some dealers feel a lot of that is already priced in and are exiting their long positions ahead of the meeting in Vienna.'
It was a similar story on the FTSE 250 and Small Cap indices, where oil stocks slumped. Tullow Oil (TLW) was down 4.5% at 168.6p, EnQuest (ENQ) fell 7% to 24p and Premier Oil (PMO) was down 2.9% at 110.5p.
Miners meanwhile tracked a fall in metals prices, amid fears over weakening demand from top metals consumer China.
(10:38) Aviva rallies on £1bn buyback report
Aviva jumped 1.7% to 508p, helping the UK blue-chip index rise 17 points, or 0.2%, to 7,427.
The Sunday Times said chief executive Mark Wilson was expected to reveal the buyback this week, citing estimates from analysts at Barclays that the insurer had £1.5 billion of excess capital to deploy.
Easyjet (EZJ) was meanwhile the FTSE 100's biggest riser, up 2.1% at £13.94 after an upgrade from analysts at Exane BNP Paribas, to 'neutral', from 'underperform'.
Micro Focus (MCRO) fell to the bottom of the index, down 2.9% at £25.78, after Deutsche Bank analyst Steve Goulden downgraded the software group to 'hold' from 'buy'.
'With limited upside to our price target, we believe the risk / reward is now rather more balanced,' he said.
Shares in Centrica (CNA) meanwhile continued to languish, down 1.8% at 136.5p, after last week's profit warning sparked a downgrade from analysts at Bernstein, who cut their rating to 'market perform' from 'outperform'.
Pearson (PSON) fell 1.8% to 695.5p as the educational publisher sold its Wall Street English language teaching business for $300 million (£225 million).
However, the sale will only reduce debt by $100 million due to $50 million of costs and the fact $150 million will sit in the disposed business.
'The latter point will be of particular disappointment to investors who would have been looking for bigger cash proceeds,' said Ian Whittaker, analyst at Liberum.
'It also explains why the business was able to be sold at such a high headline figure.'