The FTSE-100 closed 2.2 points lower at 5869 as rival political leaders in the US discussed how to avoid a raft of automatic tax hikes and spending cuts next month.
There was further disappointment earlier over Monday's weaker-than-expected US manufacturing report revealing a contraction in the sector in November.
Investors were nervously awaiting today's autumn statement from Chancellor George Osborne, in which he is expected to change or abandon his goal to cut the UK's debt as a percentage of GDP by 2015/2016.
Loading article content
Fears that political leaders will fail to secure a budget deal meant New York-listed oil prices dropped towards $88 a barrel.
The pound was up against the US dollar at 1.60 as the manufacturing figures hit the greenback. Sterling was down against the euro at 1.23.
This had an impact on BP, which was 1%, or 5.9p, lower at 424.3p, while in the mining sector Randgold Resources was 185p down at 6480p.
Tullow Oil was a big faller as it said an appraisal well off French Guiana had not encountered hydrocarbons. Shares fell 6%, or 79p, to 1292p.
Financial stocks did their best to prop up London's top flight, with Royal Bank of Scotland up 3.1p to 295.7p and Lloyds Banking Group 0.2p higher at 45.9p. In the insurance sector, Aviva was 4.7p stronger at 355.5p and RSA cheered 1.4p to 120.7p, a 1% rise.
Supermarket Tesco gained as investors positioned themselves for a potential surprise in today's trading update. Analysts are currently forecasting a return to sales falls as general merchandise continues to take a hit.
A survey of till rolls by Kantar Worldpanel showed Tesco saw growth of 2.2% in the 12 weeks to November 25, giving it a market share of 30.7%. Shares rose 4.2p to 326.7p.
Sainsbury's continued to outperform its rivals by snapping up a share of 16.9% for the same period, although its shares dropped 0.3p to 337p yesterday.
Morrisons fell 1.9p to 264.3p after Kantar said its market share dropped to 11.7% from 12.3% a year earlier.
Holiday company TUI Travel made headway after reporting an 8% rise in underlying pre-tax profits to £390 million for the year to September 30.
Holidays targeted at couples and those looking for luxury all-inclusive resorts drove the record performance.
Shares were 9.1p higher at 278.1p, a rise of 3%.