The tax office has written to thousands of people whose details were included in a fraud alert system even though there was no reason to suspect them of wrongdoing.

The Fraude Signalering Voorziening (FSV) was used for eight years to flag up irregularities in applications for benefits or tax returns. But the system also led to people being labelled as suspected fraudsters because of technical errors such as leaving a signature off a form.

The blanket use of anti-fraud measures was one of the mechanisms criticised in the report on the child benefits scandal that led to the downfall of Mark Rutte’s last cabinet in January.

In the letter, sent to 60,000 people, the tax office says it shut down the FSV system in March last year because it failed to comply with Dutch privacy law. Restrictions on who could access information were not strict enough and information was retained beyond the expiry date.

The consequences varied enormously. While some families had to pay back thousands of euros in childcare allowances and barred from claiming in future years, leading to financial ruin in some cases, others were unaware their names were included until they received the letter this week.

‘We don’t understand why we got this letter,’ Linda Renkli told NOS. ‘We always paid our taxes on time and never used benefits or subsidies. But we’re going to look into it. Even though we weren’t disadvantaged, just the fact that people were put on such a list is unacceptable.’

‘For a lot of people there were nothing more on them in the system other than their personal details,’ a spokesman for the tax office said. ‘We are also investigating whether and how we can inform people about the reason they were registered in the FSV.’

The letter includes details of how recipients can find out what information was held on them in the fraud indication system. It admits that in some cases people’s names were added simply because their local council or the employment insurance agency UWV requested details of their income.

Socialist Party leader Lilian Marijnissen has submitted a motion in parliament stating that the tax office should be responsible for informing people of how their information was used, rather than the affected individuals having to seek clarification themselves.