The latest optimism came from the World Bank as it said the global economy was now at a turning point, with growth expected to firm from 2.4% in 2013 to 3.2% this year and 3.4% in 2015.
With America's Dow Jones Industrial Average recovering from losses at the start of the week to finish higher in Tuesday's session, the FTSE 100 Index continued its run of form to close 53 points up at 6819.9.
Meanwhile, Germany's Dax reached new all-time highs as it climbed 2% while France's Cac 40 leapt 1% on the mood of global optimism.
The better picture from America saw the greenback make gains against sterling, which dropped a cent to 1.64 US dollars.
The pound was flat against the single currency at 1.20 euros.
In London, luxury goods retailer Burberry was one of the biggest risers in the top flight after third quarter retail revenues jumped 14% to £528 million in the three months to December 31.
Like-for-like growth was in line with expectations at 12% and reflected more strong demand in China. Burberry rose 68p at 1537p, a gain of nearly 5%.
Other strong performances were seen in the insurance sector after Edinburgh-based Standard Life rose 8.8p to 385.9p on the back of a broker upgrade from Credit Suisse. Prudential added 27p to 1377p.
Energy suppliers SSE and entrica were among the heaviest fallers after Barclays warned of an "inevitable" margin squeeze as political pressure was likely to limit the consumer price hikes needed to offset declining consumption and other cost pressures. SSE, which owns Southern Electric, fell by 29p to 1320p and British Gas firm Centrica slid 11.5p to 315.5p.
Financial services firm Hargreaves Lansdown was 4% lower after it announced a shake-up of charges for its investor clients.
It estimates overall charges will be cut by £8 million over the first year, at a cost to the group's revenues.
But it cautioned there may be a further £9 million hit after April 2016.
The group said it would need to bring in around £3.5 billion of new business over the next three years to offset the cost of the changes - adding that benefits of previous price cuts had outweighed the impact.
Shares still fell 62p to 1446p as analysts at Canaccord Genuity cut their full-year profits forecast for the 2014/15 year by 3%.
The biggest FTSE 100 risers were Anglo American, up 70p to 1332.5p, Burberry, GKN, up 12.4p to 403.6p and G4S, up 7.9p to 258p.
The biggest FTSE 100 fallers were Hargreaves Lansdown, Centrica, Imperial Tobacco, which was down by 68p to 2185p, and SSE.