The FTSE 100 Index is up 16.2 points at 6,083.2 points this morning, having earlier hit 6,092.5 points - its highest intraday level since February 2001.
The risers are dominated by the mining sector following a strong performance by Australian-listed miners overnight as investors said booming demand for raw materials will continue to keep prices high.
Antofagasta is up 2.49% at 2,387p, BHP Billiton has gained 1.75% to 1,162p, Rio Tinto has risen 1.89% to 3,174p and Xstrata has gained 2.48% to 2,023p.
Marks & Spencer has bucked a lacklustre trend in the retail sector with forecast-smashing results. Its shares are up 4.26% at 588p.
On the downside, shares in Prudential have eased 0.52% to 664p as credence over takeover speculation - the main driver of Prudential's share price in recent weeks - was knocked by news France's AXA is not interested in the UK company.
Scottish & Newcastle has also lost 1.88% to 521.50p on news it is raising cash through a share placing to fund its proposed acquisition of the Foster's brand in Europe.
In Japan, the Nikkei 225 Stock Average dropped 38.45 points, or 0.2%, to 17,418.13 points, paced by semiconductor-related shares after brokerages cut ratings on Advantest and US rivals.
Advantest slid 420 yen, or 2.8%, to 14,580 and Tokyo Electron slumped 270 yen, or 3.2%, to 8,170.
But losses were limited as commodity stocks such as Inpex rose after prices for oil, copper, zinc and nickel jumped to records in London.
Inpex advanced 30,000 yen, or 2.4%, to 1.26m. The company uses benchmark prices in London to price oil produced in areas including the Caspian Sea which forms part of Iran's northern border.
Sumitomo Metal Mining added 24 yen, or 1.4%, to 1,741 and Nippon Mining Holdings surged 73 yen, or 7.1%, to 1,097 as copper futures in Shanghai rose to a record for a sixth day.
In the US, the Dow Jones industrial average rose 21.29 points, or 0.19%, to end at 11,141.33 points as rising oil prices helped lift energy shares such as Exxon Mobil.
Exxon Mobil rose 1%, or 61 cents, to $61.94, while Chevron gained 1.8%, or $1.07, to $59.72.
Shares of Boeing hit an all-time high of $80.92 on hopes for more plane orders. The stock closed at $80.79, up 1.5%, or $1.22.
JPMorgan Chase rose 0.4%, or 18 cents, to $41.88 after the bank said it will swap its corporate trust unit, valued at $2.8bn, for Bank of New York's 338 retail branches and small business banking network, valued at $3.1bn.IFAonline
Partner Insight Video: Advisers have had to adapt to the changing investment landscape.
Investment trust savings scheme