Blue chip shares struggled for direction with just two days to go until the general election.
The FTSE 100 Index fell 17.1 points to 7508.7, with traders keen not to take too many risks until after voting booths close on 8 June. The FTSE 250 Index, a closer indication of the health of UK firms, was 228.5 points lower at 19640.2.
Investors are finding it hard to call this election, with polls fluctuating wildly, reflecting different methods of data collection.
One poll by Survation for ITV out overnight showed the Tories just one point ahead of Labour, against a six-point lead a week ago.
IG market analyst Joshua Mahony said: "There is no doubt that the contest is looking a lot more unpredictable than when Theresa May called the election."
Royal Bank of Scotland (RBS) was almost 2% lower after the lender agreed a £200m ($258m) settlement with investors who say they were misled during a right's issue prior to the lender's near collapse in 2008.
A spokesperson for the RBS Shareholder Action Group said that it has "accepted legal advice and the matter will not now go to court".
The RBoS Shareholders Action Group has voted to accept a 82p a share offer, well below the 200p-230p a share that investors paid during a £12bn fundraising nine years ago.
However, the bank, 72%-owned by the taxpayer, still has to settle claims with the US Department of Justice that it mis-sold toxic residential mortgage-backed securities in the run-up to the financial crisis. Shares in RBS fell 4.9p to 254.8p.
The biggest afternoon risers in the FTSE 100 Index were Randgold Resources (+180p to 7680p), Fresnillo (+36p to 1658p), EasyJet (+14p to 1358p), Reckitt Benckiser (+83p to 8070p) and Associated British Foods (+29p to 3017p).
The biggest afternoon fallers in the FTSE 100 Index were (-17.2p to 326.8p), Burberry (-55p to 1755p), Merlin Entertainments (-15.5p to 508.5p), Old Mutual (-5.8p to 195.7p) and Kingfisher (-9.3p to 317.3p).
The biggest afternoon risers in the FTSE 250 Index were Clarkson (+111p to 2612p), Acacia Mining (+10p to 295.7p), Hochschild Mining (+4.5p to 301.4p), Weir Group (+24p to 1840p) and Centamin (+2.1p to 170.1p).
The biggest afternoon fallers in the FTSE 250 Index were AO World (-10.8p to 134.2p), Sophos Group (-27.4p to 421.6p), HarbourVest Global Private Equity (-52p to 1252p), Hunting (-17.6p to 482.4p) and RPC Group (-30.5p to 842.5p).