(Corrects milestone for unemployment data)
LONDON, March 15 (Reuters) - Sterling fell back below $1.22 on Wednesday, halving the day's gains, after data for the three months to January showed a deeper-than-expected fall in the pace of wages growth, the latest sign a previously robust economy may be stuttering.
Britain's unemployment rate fell unexpectedly to its lowest since 2005, the data showed, but pay growth worsened to 2.2 percent, its weakest since last April, at a time when inflation is rising.
The pound fell from around $1.2230 before the data to $1.2193 by 0947 GMT, still up around 0.3 percent on the day but down from an earlier high of $1.2258.. The numbers also ate into its gains against the euro, leaving it up just 0.1 percent at 87.15 pence to the single currency.
London's main FTSE stock exchange index, whose internationally-focused stocks tend to gain when sterling weakens, turned higher after the data to stand 0.3 percent up on the day.
"It is just these weak numbers that have driven this," said the head of currency dealing with one international bank in London. (Reporting by Helen Reid, Patrick Graham and Ritvik Carvalho; Editing by Jemima Kelly)