British real wages are expected to climb early in 2020 to levels not seen since before the financial crisis over a decade ago, a think-tank forecast on Friday.

Pay data adjusted for inflation will be strong at the start of the new year despite economic growth remaining sluggish, raising concerns that the turnaround may not be sustainable, the Resolution Foundation said in its earnings outlook.

Growth in the world's fifth-biggest economy has slowed since voters decided in June 2016 that Britain should leave the European Union.

The labour market, however, has fared well in 2019, with the unemployment rate recently falling back to its lowest level since early 1975.

"The big question for 2020 is whether (the labour market) can continue its strong run, or whether it will reach a tipping point and reconnect with weaker growth performance," the Resolution Foundation said.

The foundation said falling vacancies and rising youth unemployment were worrying signs for the market, while earnings were at risk from staggering productivity and weaker nominal wage growth.