However, the market closed below its intra-day highs after energy stocks fell on oil prices, which dropped following a report showing higher U.S. stocks and concerns about the commodity's global demand.
The market also came under some pressure after U.S. Federal Reserve Chair Janet Yellen said a rate hike in December was a "live" possibility, but not a certainty.
The blue-chip FTSE 100 index ended 0.5 percent higher at 6,412.88 points after rising to 6,459.46 points, the highest since late October.
British retailer Marks and Spencer advanced nearly 3 percent after it raised its annual non-food profit margin forecast and beat first-half profit estimates.
"Improvements to both underlying profits and earnings per share are potential indicators to a generally improving trend," Richard Hunter, head of equities at Hargreaves Lansdown, said.
"The largest challenge remains in the form of sales within General Merchandise, where M&S is focusing on margin improvements by eschewing discounts and concentrating on full price sales. This buys the company some time to rediscover the magic potion which may tempt younger shoppers into its stores."
The UK mining index surged 1.8 percent, the top sectoral gainer, helped by a rally in metals prices. Trader and miner Glencore led the index higher, with its shares rising 5.4 percent after saying it was on track to reduce its debt to $20 billion from $30 billion.
Glencore also plans to boost liquidity with asset sales and to cut copper output further to help lift prices.
"Given how heavily they've fallen and then subsequently rallied thereafter, we still think they represent good value alongside some other picks in the mining sector," said Atif Latif, director of trading at Guardian Stockbrokers.
Other miners were also up, with Anglo American, BHP Billiton and Rio Tinto rising 1 to 3 percent.
However, British housebuilders fell, with Berkeley, Persimmon, Taylor Wimpey and Barratt Developments down 2.3 to 3.9 percent. Traders cited concerns over possible interest rate hikes and valuations in the sector.
Among mid-cap stocks, property services company Countrywide slumped 11 percent after it said that its full-year core earnings would be down 2014. Estate agency Foxtons Group was also down, falling 5.6 percent.
(Additional reporting by Atul Prakash; Editing by Ralph Boulton)
By Kit Rees and Atul Prakash
