One third of the 22 million public transport smart cards which have been issued so far have been lost or are no longer valid, the card’s operator Translink told the Telegraaf on Friday.

The ov-chipkaart was first introduced in 2005 and replaced all paper tickets on trains this July. That helped drive the total number of transactions last year to over 2.1 billion, the Telegraaf said.

A replacement card for people who have an ov-chipkaart registered in their name costs €11 and the balance can be returned to their bank accounts.

The Telegraaf report did not say how much money travellers with anonymous cards have lost.