BoE Governor Mark Carney and his top officials reiterated that they might raise borrowing costs more than investors expect over the next three years, possibly within a year.
But markets focussed on the Bank's lowering of its 2017 growth forecasts, to 1.7 percent from 1.9 percent in May, as well as its unexpected reduction of its inflation projections, which it put at just under 2.6 percent in a year's time after peaking around 3 percent in October.
"The 6-2 vote was as expected. However, the dovish growth and inflation (forecasts were) a surprise to the markets," said Mizuho's head of hedge fund FX sales, Neil Jones.
After Carney said in a press conference that business investment was likely to be negatively affected by Brexit, with bad consequences for productivity and wage growth, sterling fell as low as 90.485 pence per euro, the weakest since early November <EURGBP=D3>.
It also fell over a cent against the dollar to a three-day low of $1.3113 <GBP=D3>, having earlier reached an 11-month high of $1.3267 against the U.S. currency.
Although most economists taking part in a Reuters poll had forecast a 6-2 vote to keep rates on hold, some had thought that chief economist Andy Haldane could join those calling for an immediate increase.
At the last meeting, three rate-setters voted to raise rates, but one, Kristin Forbes, has since departed and been replaced by the more dovish Silvana Tenreyro.
"The market hadn’t priced in much possibility of a hike this month, but the 6-2 vote was a bit of a dovish surprise for us," said Yujiro Goto, an analyst at Nomura, one of the only banks that had been calling for a rate increase this month.
For a Reuters graphic on views of the Monetary Policy Committee's members, click on: http://tmsnrt.rs/2eSYykb
The Bank also kept its asset-purchase programmes unchanged and said a bank lending scheme would end as previously scheduled in February 2018.
A few weeks ago, investors had begun to price in a chance that the BoE might raise interest rates for the first time in a decade this month, after a series of hawkish remarks by policymakers, including Carney and Haldane.
But a raft of weaker data - as well as deep uncertainty about the impact of Brexit - called that view into question. Recent figures showed the economy had its slowest growth since 2012 in the first half of this year, while inflation has also dipped and growth in wages remains weak.
Divorce talks between Britain and the rest of the EU have had a stumbling start, leaving many companies nervous about the risk of a damaging departure from the bloc in 2019.
"The reality is that we’re facing an uncertain period, and neither markets nor companies like uncertainty," said Mark Horgan, chief executive of foreign exchange provider Moneycorp.
"The market has been spooked by the 1.7 percent growth forecast ... In any market where your inflation is greater than your growth forecast, you’ve got a problem."
Earlier, a purchasing managers' index (PMI) survey for Britain's dominant services industry showed a slight pick-up in July to 53.8, which came as a relief to those worried about an economic slowdown and sent sterling briefly higher.
By 1530 GMT, sterling was trading down 0.6 on the day at $1.3142, and down 0.8 percent at 90.40 pence per euro.
(Editing by Larry King)
By Jemima Kelly