US Federal Reserve head Jerome Powell told the annual Jackson Hole summit of central bankers his organisation will do whatever it takes to control inflation.
The FTSE 100 kept its positive momentum thanks to a rally in mining and oil stocks.
BP and Royal Dutch Shell both enjoyed gains of at least 1%.
The blue-chip index closed 0.2% higher at 7,577.
In the US, sentiment was also strong with the S&P 500 rising 0.5% to 2,872 around 4:45pm UK time.
Brent crude oil surged 1.8% to $76.11 per barrel. Copper climbed 2.1% to $2.71 per pound and gold gained 1.7% to $1,207 per ounce.
MID AND LARGE CAP RISERS AND FALLERS
Pharma giant Shire announced its preventative drug for hereditary angioedema, Takhzyro, has been approved by the US Food and Drug Administration, giving the shares a 2% boost to £45.13.
IT infrastructure specialist Computacenter revealed a strong performance in its first half as pre-tax profit and sales both increased. The market took the news in its stride as the shares were flat at £14.96.
SMALL CAP RISERS AND FALLERS
Shares in Bahamas Petroleum plummeted 68.8% to 1.9p after it revealed an exclusivity deal with an undisclosed oil major is to expire at the end of August.
Building materials firm Kingspan pleased the market with rising sales, profitability and a hiked half year payout, pushing the stock 7.8% higher to 42.4p.
Construction business Henry Boot strengthened 5.3% to 285p after pre-tax profit jumped 15.9% to £26.2m in the first half of 2018.
Mining small cap Kefi Minerals announced a consortium of Ethiopian investors would help fund its projects in the country, which are forecast to be worth between $30m and $35m. Investors marked the stock 7.3% higher to 2.2p.