Buoyant investors pushed London’s FTSE 100 above 6,300 for the first time since May 2008.
The benchmark index was up 24 points, or 0.4pc, at 6,308 in mid-afternoon trade after fresh durable-goods data from the US beat market expectations and boosted trader confidence.
The index has already gained almost 7pc since the beginning of 2013, its best start to a year since 1989, with many in the market speculating the move could herald a broader shift into equities from bonds.
"Equities are in rude health, and analysts are rushing to talk up their quality and call the start of the next bull market," said Will Hedden, a sales trader at IG.
"What puzzles many is that we have come so far from 2008 lows, yet only now are we contemplating the start of a great period for equities – one in which 7,000 and new territory looks very possible for 2013."
The New Year’s Day compromise deal on the US "fiscal cliff" – tax rises and spending cuts that threatened to push the country back into recession – and encouraging data from China helped equity markets experience a strong start to 2013.
By and large, investors have remained positive in the outlook for the global economy ever since, which has helped sustain the rally.