“SERIOUS problems” in public services will get worse if wages continue to fall behind the cost of living, the Unison union has warned in a letter to Boris Johnson.

General secretary Dave Prentis wrote to the Prime Minister urging him to invest in public-sector workers after years of pay cuts and job losses.

Mr Prentis said the new PM had a “duty” to take action to ease the financial strain on workers, whose income is slipping further behind as the cost of living rises.