The FTSE 100 Index was lodged in a narrow trading range throughout the session and closed just 5.2 points above its opening mark at 3942.1.
Oil stocks have pushed ahead, benefiting from the threat of war in Iraq and continuing concern over how the national strike in Venezuela will affect demand.
BP put on 3p at 429p and Shell surged 7.75p to 416.25p, its highest point for nearly a month.
Other heavyweight stocks adding some support included BHP Billiton, the day's biggest riser with a 7.5p climb to 330p.
But retail stocks were under pressure in the wake of reports of sluggish festive demand on the UK's high streets.
As the last remaining hours of Christmas shopping got under way, those on the way down included J Sainsbury, off 2.25p at 272.25p, GUS, 5.5p lower at 566.5p, Next, down 7.5p at 734.5p and Marks & Spencer, 6.75p weaker at 307.75p.
Among the FTSE 250 retailers, Woolworths slipped 1.5p at 35.75p and MFI Furniture lost 4.75p at 105.25p.
But charter airline firm Excel Airways flew ahead 10% - up 15p to 168p - after reporting a jump in turnover and underlying profits in its first set of results since listing last month.
And Network Technology shot ahead 10% despite warning the City not to expect a full recovery in most of its hard-hit markets until 2005.
However, it added that its core US market should see an improvement sooner and the shares added 0.25p at 2.75p
PA