Ikea has admitted some of its suppliers used political prisoners as forced labour in East Germany under the Communist regime.

The Swedish furniture retailer said it “deeply regrets” the involvement of prisoners following a study it commissioned from accountants Ernst & Young into the matter, which occurred in the 1980s.

The study found Ikea knew that its suppliers were using political prisoners of the Stasi, the notorious East German secret police, to manufacturer goods.

Ernst & Young studied 20,000 pages of documents from Ikea’s internal records and 80,000 archived items from German federal and state archives in compiling the study. It also interviewed 90 people, including present and former Ikea employees and witnesses from the former GDR.

Ikea’s sustainability manager Jeanette Skjelmose said: “We deeply regret that this could happen. Using political prisoners in production has never been accepted within the Ikea Group.”