Boomer generation's retirement will hurt economy Lower immigration will also contribute to an economic slowdown that threatens to overshadow this decade 5 April 2021 • 7:02pm Britain’s ageing population and lower rates of immigration will put the brakes of economic growth in the 2020s, City forecasters have warned. The supply of labour will be curbed by the Boomer generation retiring and an immigration clampdown, halving the growth rate in the workforce, according to Pantheon Macroeconomics. Growth in workers will slump to an average annual rate of just 0.3pc over the next five years, down from 0.8pc in the second half of the 2010s, it predicted.