Leading shares remained firmer in thin midday trade, just holding off earlier highs hit ahead of the midmorning futures and options expiries, supported by expectations for a solid opening advance today on Wall Street, dealers said. At 11.57 am, the FTSE 100 index was 39.1 points firmer at 5,308.4, just holding off the morning peak of 5,312.6. All the broader FTSE indices were also higher. Volume was low, with 860 mln shares changing hands in 76,084 deals. Looking ahead to Wall Street, spread betters IG Index expect the DJIA to open around 26 points firmer at 10,580 today, following yesterday's mixed performance. But with triple-witching futures and options expiries today, a lack of economic or corporate news across the Atlantic, and oil prices remaining stubbornly high the mood is expected to remain volatile. Oil futures rallied today in London as dealers took the opportunity to aggressively buy in the dips, while prices were also supported by Ecuador halting its oil exports to the US amid violent protests in the country. Front month October-dated Brent futures contracts were up 1.05 usd a barrel at 63.45 usd a barrel, trading below Monday's record of 66.85 usd. Gains by oil issues helped fuel the FTSE 100 rise at midday, with Royal Dutch B shares up 32 pence at 1,872 and BP ahead 9 pence at 633 in tandem with the crude price strength. Strength among the miners also remained a prop for blue chip issues, with the sector rallying after a weak performance over the last couple of days as copper prices rebounded. In response, Rio Tinto shares added 29 pence at 2,007, BHP Billiton gained 12-1/2 pence at 819, and Xstrata took on 14 pence at 1,292. There was little corporate news to drive other interest, with broker comment and press reports providing the main features. Shares in Carnival topped the FTSE 250 leaders board, adding 77 pence at 2,984 amid press reports that the US State Department has withdrawn its proposed deadlines for passport requirement to the Caribbean, Mexico and Canada. In reaction, Deutsche Bank noted that although passport requirements must still be implemented by Jan 1, 2008 and tighter security appears inevitable, it now seems likely that the Dec 31 deadline, which would have required passports for US travel to the Caribbean, will be delayed.