An algorithm used to determine UK citizens' welfare benefits caused hunger, debt, and psychological distress, a human rights organisation warned.

Human Rights Watch discovered that the model, which calculated the benefits people are entitled to each month based on changes in their earnings, only analysed the wages people received within a calendar month, and ignored how often they were paid. 

This resulted in people receiving multiple paychecks per month - a common occurrence in irregular and low-paid work - having their earnings overestimated and their payments shrunk significantly. 

The incident is one of many affecting the UK's Universal Credit system, of which the model forms a core part. Universal Credit combines six benefits into a single monthly sum.