The London market rose strongly in early trading, which some traders attributed to Donald Trump's speech to Congress overnight.
The benchmark FTSE 100 index jumped 0.75% to 7,317 points.
Connor Campbell of Spreadex said: "The bar is so low with Trump that something resembling a 'presidential' performance can bring relief to investors."
Mr Trump pledged $1 trillion in infrastructure spending and "massive" tax cuts for the middle classes.
However, he did not detail how any of it would be paid for.
Greg McKenna, chief market strategist at AxiTrader, said it was a "bit of a disappointment in the sense that he did not put any more meat on the bones" of past promises.
Next was the biggest riser on the FTSE 100, up 3.6%.
BHP Billiton and Glencore both added 2.5% and 2.3% respectively, although fellow miner Fresnillo shed 2% to make it the biggest faller.
ITV added 1.6% after announcing a £200m special dividend with its annual results.
On the FTSE 250, Mitie Group added 5.3% after selling its troubled social care businesses for a nominal £2 to private equity firm Apposite Capital.
On the currency markets, the pound was flat gagainst the US dollar at $1.2377 and up 0.25% against the euro at 1.1734.