Ms M’s address details were held by a number of government agencies, including HM Revenue & Customs, the Child Support Agency and the Department for Work and Pensions. In 2006 her personal details were wrongly changed on one agency’s computer system to show her living at her former partner’s address. These incorrect details spread across a network of government computer systems and as a result, Ms M’s personal financial information was sent to her former partner, and her child support entitlement was incorrectly reassessed and reduced without her knowledge.

Ms M’s MP referred her complaint to us.

Our investigation found it likely that Ms M’s address was incorrectly changed due to an error by the Tax Credit Office that spread across the computer network. None of the bodies involved accepted responsibility; they blamed each other and ‘the system’ for the mistake.

We upheld the complaint and recommended that HM Revenue & Customs apologise to Ms M on behalf of all three agencies, pay her £2,000 compensation and reassure her that her details were correct. We also recommended that the agencies work together to decide how to respond to complaints of this kind in future. The Cabinet Office agreed to issue guidance across government to ensure that lessons from Ms M’s experience were learnt.