British unit labour costs, a gauge of competitiveness, rose by 2.1% in the first three months of the year compared with the same period of 2018, the sixth consecutive quarter of growth of more than 2%, official statistics showed.

"Our latest figures represent a continuation of the UK's productivity puzzle. This sustained stagnation in productivity in the last decade is at odds with what we've seen after previous economic downturns," Katherine Kent, an official with the Office for National Statistics, said.