British industrial output suffered its sharpest monthly drop in December since 2012, new figures show.
Warmer than usual weather curbed demand for electricity and gas and manufacturing continued its decline, denting hopes for improvement this year.
Britain has been one of the fastest-growing major advanced economies in the world for the last couple of years.
But it has relied heavily on domestically focused services for growth, frustrating plans for a better-balanced recovery.
UK industrial output fell 1.1% month-on-month in December after a 0.8% drop in November, the Office for National Statistics said.
This was worse than all forecasts in a Reuters poll of economists that predicted a 0.1% dip.
The figures add to a run of poor industrial output data from countries around Europe, including France and Germany, and is unlikely to allay worries about the global economy's health.
The ONS revised down its estimate for industrial output in the fourth quarter to show a 0.5% drop from a 0.2% decline previously, reflecting a sizeable fall in electricity generation caused in part by unusually mild weather.
The UK economy expanded 0.5% in the fourth quarter, but this early estimate could easily be trimmed if poor construction output numbers on Friday follow the industrial data, analysts say.
The manufacturing sector failed to contribute to British economic growth in 2015 and the latest figures do not augur well for this year.
Output in manufacturing fell for a third month in a row for the first time since early 2009, dropping 0.2% on the month after falling 0.3% in November. Economists had expected output to edge up 0.1% in November.
Meanwhile, a separate survey from the Bank of England's regional agents also showed a slowdown in manufacturing, with exports suffering from the global economic slowdown.
Both industrial and manufacturing output saw their biggest annual declines in December since the middle of 2013, the data showed.
Finance minister George Osborne has warned the economy is facing a "dangerous cocktail" of risks from overseas in 2016, as growth slows in major emerging markets, stock markets tumble and a slump in oil prices reduces demand from oil-exporting nations.
Output from the oil and gas extraction sector fell 4.6% on the month, the biggest decline since September.
Brent crude oil prices slid 16% in December and 35% for 2015 as a whole.