New analysis for the Child Action Poverty Group (CPAG) suggests that households whose benefits are capped will be left on average £65 a week worse off from April than they would be without a cap in place.
The warning comes after the latest inflation figures released by the Office of National Statistics (ONS) show that there was a slight dip from 10.1% in July to 9.9% in August - but still substantially higher than the 3.1% benefits uprating applied earlier this year.
The September Consumer Price Index (CPI) inflation figure is released in October and is used by the UK Government to determine the benefit uprating which is applied the following year. However, CPAG said that around 120,000 households whose benefits are already capped, affecting an estimated 300,000 children, will not see any rise when benefits are increased next April in line with the current inflation rate.