The FTSE 100 soared early and then consolidated its gains in late trading to record a 119.7 point rise, or 1.93%, to close at 6308.8.
Capita Group was the day’s best performer; the business process outsourcers climbed 40.5 points, or 5.71%, to 748.5.
Standard Chartered recorded a better-than-expected 30% jump in interim profits, taking its share price up 79 points, or 5.03%, to 1638.
Vodafone also did well, up 7.6 points, or 4.91%, to 159.4.
Xstrata posted a 47% first-half in net profits rise to $3bn, in line with forecasts, but still fell 119.7 points, or 1.93%, to 6308.8.
Tate & Lyle was the only other to lose ground today, falling 3 points or 0.54%, to 558.5.
In New York, the Dow Jones started lower as cautious investors’ awaited news from the Federal Reserve on interest rates.
It has rebounded in the last moments to currently sit slightly ahead, just 1.95 points higher, to 13470.73.
American International Group, the world's largest insurer, is consolidating yesterday’s stellar gains, up 1.51 points, or 2.34%, to 66.07.
General Motors has completed the $5.6bn sale of its Allison Transmission unit, driving its price up 0.75 points, or 2.31 points, to 33.2.
Alcoa has rebounded, up 0.81 points, or 2.27%, to 36.48.
Microsoft is among the largest early losses, the computer software conglomerate is up 0.35 points, or 1.18%, to 29.19.
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‘Most significant’ upgrade since launch
Changes happening over coming months
Had accepted British Steel business
Aimed at HNW clients and family groups
Set for 1 April 2019