Blue chips stocks pushed through 6900 in afternoon trading, after the US Federal Reserve decided to hold interest rates. The FTSE 100 Index jumped 83 points to 6917.8, as the Fed last night also cut the number of rate increases they expect this year from one to two.
The FTSE 250 Index rose 55.2 points to 17989.1. Cheap cash favours investors.
IG market analyst Joshua Mahony said, as the pound rose against the dollar, "commodities in particular gained ground as a result".
Commodities trader and miner Glencore rose 11.2p to 208.3p, while silver miner Fresnillo lifted 81p to 1794p.
In afternoon trading the biggest risers in the FTSE 100 Index were Glencore (+11.2p to 208.3p), Fresnillo (+81p to 1794p), Randgold Resources (+325p to 8005p), TUI (+44p to 1093p) and BHP Billiton (+42.5p to 1093.5p).
The biggest fallers in the FTSE 100 Index were HSBC (-8.1p to580.6p), Shire (-63p to5182p), Informa (-8.5p to722p), Perason (-8.5p to 773.5p) and Whitbread (-27p to3976p).
In afternoon trading the biggest risers in the FTSE 250 Index were Hochschild Mining (+24.6p to 293.6p), Vedanta Resources (+35p to 553p), JRP Group (+6p to 126p, Evraz (+7.4p to 162p) and Investec (+16.8p to 480.3p).
The biggest fallers in the FTSE 250 Index were Ladbrokes (-6.1p to 141.4p), Countrywide (-8.7p to 217.6p), CMC Markets (-8.7p to 218p), DFS Furniture (-9p to 254.2p) and Paragon Group (-9.1p to 315p).