Strategists at US-based asset manager MFS have warned that Donald Trump will struggle to meet his 2016 pledge to achieve economic growth of 4% a year, following his inauguration as US president.

MFS chief economist Erik Weisman has crunched data which shows that GDP growth has declined in nearly every economic upswing since 1960, when it hit 4.9%. There was a marginal reversal during the mid-1980s but it skidded to 2.7% in the noughties, and 1.8% during the latest upswing starting in 2009.