It only took 15 years, but the U.K’s FTSE 100 can now claim a record closing high. The British blue-chip index UKX, +0.05% had been trading flat for much of Tuesday’s session, but it picked up enough steam during afternoon trade to push up 37.47 points, or 0.5%, ending at 6,949.63. It was enough of a move to hit a banner level for the London stock benchmark. The last closing high of 6,930.20 was reached on Dec. 30, 1999. That is when Tony Blair was the U.K’s prime minister. To further put things into perspective, that is also when the benchmark interest rate was five percentage points higher at 5.5%, the country’s minimum wage of £3.60 was ushered in, and markets were in the throes of a bubble in technology startups. A new closing high “inevitably raises questions about sustainability. “Is this a sell signal? Absolutely not in our view,” said HSBC late Tuesday, noting that the index in real terms is still 29% below its all-time high. Much of Tuesday’s heavy lifting came from BHP Billiton PLC BLT, +1.16%BHP, +1.50% BHP, +0.18% with shares of the world’s largest miner by revenue jumping 6.2% following its financial result and a dividend hike Tuesday. More broadly, cheap money, underpinned by unconventional monetary policy by central bankers around the world, has helped fuel this run-up in U.K.-based stocks, pushing gains well beyond the duration of your average length of a bull market, said Angus Campbell, senior analyst at FxPro, in a note. The acceleration of gains for the FTSE 100 Tuesday also came after debt-troubled Greece moved closer to completing an extension of its 240-billion-euro ($273 billion) bailout, and as investors appeared to embrace the U.S. central bank’s view on interest rates. Germany’s DAX 30 DAX, +0.33% also hit a fresh record close — it is 16th of the year — on Tuesday, at 11,205.74. HSBC said it expects the British benchmark to post positive returns over the next 12 months, and that it is “relaxed” about the new, high level in part because it “still offers a 3.9% prospective dividend yield, higher than many other asset classes. This may prove to be attractive to income investors.” The 10-year gilt yieldTMBMKGB-10Y, -2.11% stood at 1.76% on Tuesday. So, when will the FTSE 100 reach the so-far elusive 7,000 mark? It may not be before long, “but it looks as though the best gains have been made and further upside could be limited,” noted Campbell. Headwinds facing U.K. investors include the upcoming U.K. general election in May, and risks of a broader economic global slowdown in Europe, China and the U.S. Carla Mozee