On Wednesday, Boris Johnson will take to the Conservative conference stage to speak to the nation. On the same day, a huge chunk of that same nation (4.4m households, including 5.1 million adults and 3.5 million children) will be seeing their incomes fall as the prime minister implements the biggest overnight benefit reduction ever. Cutting universal credit by £20 a week will mean those families will typically lose 5% of their income, a scale of shock only normally seen in recessions. These cuts will not just reduce people’s incomes, they may also damage their mental health. That’s the grim takeaway from a new report studying the impact of a previous cut: the introduction in 2016 of a lower benefit cap (the maximum amount that out-of-work households can be entitled to). The average income reduction for those affected by the cap is £2,600 a year. Those at risk of having their benefits capped already had higher levels of depression and anxiety than the rest of the population, but the reduction in the cap saw around a 10 percentage points rise in those conditions in following years. Johnson might not dwell on the huge hit to lower-income Britain taking place as he speaks but for the millions affected, the cut to universal credit will leave a much longer lasting impression than his words, given the damage to their family finances and, potentially, their mental health. Torsten Bell is chief executive of the Resolution Foundation. Read more at resolutionfoundation.org