Britain's economy ended 2015 at a steady pace amid global economic uncertainty, with quarterly growth picking up slightly to 0.5 percent in the last three months of the year compared with 0.4 percent in the previous three months.

The Office of National Statistics said Thursday that preliminary estimates showed full-year growth slowed to 2.2 percent from 2.9 percent the year before.

Treasury chief George Osborne, who has warned of a "dangerous cocktail of new threats" to the economy, nonetheless said data showed the U.K. was "pushing ahead."

Chris Williamson, chief economist at Markit, says uncertainty about whether Britain will leave the European Union and financial market volatility "are all creating an unsettling business environment and point to downside risks to the economy in 2016."