“Serious failings” led to the council tenants in Cambridge being overcharged for rent, the Regulator of Social Housing (RSH) has said. Cambridge City Council announced earlier this year that it had identified errors in how it had set its rent and service charges, with some errors going back 20 years. The authority referred itself to the regulator after it identified the mistakes. RSH has now said “significant improvement” is needed at the city council. Two historic errors were identified by the city council in how it had set its rent and service charges. The first error related to a failure to…