A data breach on the Civil Service Pension Scheme portal last week meant some members of the scheme received personal data relating to other members.
Capita said 138 members of the scheme either received personal Annual Benefit Statements data belonging to other members and/or had their personal data seen by other members.
In an update to members, the firm said the breach was “identified quickly, ABS functionality was immediately suspended, and a full investigation undertaken”.
The firm said all impacted members would be written to by 9am on 3 April 2026 via secure message. It said that, for members who haven't received correspondence, this means their data was not impacted in any way.
“We sincerely apologise for this issue and any concerns you may have,” Capita said. “We take the protection of members’ personal data extremely seriously.”
It added that ABS request functionality on the portal remains offline whilst it fixes the underlying cause of the breach.
A Cabinet Office spokesperson said: "We are aware of the incident and take the issue extremely seriously.
“While only a very small number of members were affected, we are working with Capita to establish the facts and ensure appropriate measures are taken. We will consider further action as required.”
Commenting on the breach, Fran Heathcote, the general secretary of the PCS union, said: “This is yet another hammer blow to members’ confidence in the administration of their pensions.
“This government came to office promising the biggest wave of insourcing in a generation. With every failure like this, the case for bringing essential services back in-house gets stronger.”
The incident comes amid a crisis in the 1.7 million-member scheme following the transfer of its administration from MyCSP to Capita, with thousands of retired civil servants being left without regular payments or lump sums in recent months as Capita has struggled to deal with an inherited backlog of more than 80,000 cases.
Capita has committed to provide normal service levels by the end of June. Chris Clements, managing director of Capita Pension Solutions, told CSW last month that members will also experience a "smoother, more intuitive service through the portal and a new mobile app, making it easier to access their pension information".