LONDON--U.K. unemployment fell in February below a threshold set by the Bank of England, official data showed Wednesday, a fall that will prompt officials to reassess their interest-rate stance next month.

The Office for National Statistics said the jobless rate in Britain averaged 6.9% between December and February, down from 7.1% during the previous three months. That is the lowest jobless rate since February 2009.

The decline takes the unemployment rate below a threshold set by the Bank of England in August. Officials pledged then not to consider a rise in interest rates until joblessness reached 7%.

The decline is unlikely to make the BOE alter course. BOE Gov. Mark Carney in March said policy makers have started looking at a broader range of labor market and other economic indicators to gauge how much slack there is in the U.K. economy and to judge when to raise rates. With inflation subdued, economists expect the BOE to keep its benchmark interest rate at a low of 0.5% until early next year.

Wednesday's data also show a long squeeze on Britons' earnings appears to be nearing an end. Rising prices have outstripped increases in the average Briton's paycheck for more than half a decade, hurting households' spending power and crimping consumption.

Now wage growth looks set to overtake inflation. The ONS said Wednesday that average weekly earnings, including bonus payments, grew 1.7% in the three months to February, compared with the same period a year earlier, up from 1.4% growth in the previous three months. Annual inflation was 1.7% in February and slowed further, to 1.6%, in March.

Write to Jason Douglas at jason.douglas@wsj.com and Ilona Billington at ilona.billington@wsj.com.

Subscribe to WSJ: http://online.wsj.com?mod=djnwires