Mining companies were the top sectoral gainers, with the FTSE 350 Mining index rising nearly 1 percent as a weaker dollar helped copper prices climb to two-week highs.
Shares in Anglo American, BHP Billiton, Glencore, Antofagasta and Rio Tinto rose 1.2 to 1.9 percent.[MET/L]
"A slightly weaker dollar plays in favour of commodities and their extractors, be they miners or drillers," said Mike van Dulken, head of research at Accendo Markets. "An array of recent concerns appear to have been stowed away by bulls who remain fixated on re-igniting this week's rally."
The FTSE 100 index finished 0.04 percent higher at 6,265.65 points after climbing to 6,281.73, its highest since late April.
However, the oil and gas index fell 0.3 percent as oil prices retreated, after rising above $50 a barrel for the first time in nearly seven months.
Banks also came under pressure. Analysts said investor sentiment was hurt by a surprise rights issue by Spain's Banco Popular, fuelling fears that others in the region may follow suit, to strengthen their balance sheets.
Standard Chartered, Lloyds and Royal Bank of Scotland fell 1 to 2.9 percent.
Carnival, DCC and Whitbread, down 2.5 to 3.2 percent, were among the shares going ex-dividend, so the stocks traded without the rights to their latest dividend pay-out.
Outside the blue chips, newspaper publisher Daily Mail and General Trust slumped 10.8 percent after it lowered its full-year outlook. A downturn in print advertising was hurting margins in its media business, the company said, leading to an 11 percent drop in first-half profit.
By Atul Prakash and Kit Rees