Campaigners fighting for the victims of the Post Office’s allegedly malfunctioning Horizon accounting system are claiming a breakthrough, after Post Office management called for any current users of the system experiencing problems to come forward without risk of reprisals.

For a decade, users of the system have reported unexplained losses and accounting errors, which have seen independent subpostmasters suffering financial penalties, loss of livelihood and even prison sentences. The Post Office has to date consistently stated that there is no fault with the system but, in an apparent softening of its stance, has now agreed a process and timetable for victims to come forward.

A campaign group, the Justice for Subpostmasters Alliance (JFSA), was formed in 2011 and already represents over 100 operators with outstanding Horizon claims, providing them with legal advice and access to an independent forensic accountant.

Until the end of February 2013, the ongoing inquiry will also accept instances of anyone currently working with Horizon who has examples of failings in the system in confidence and without fear of reprisals from the Post Office. Retailers concerned are being encouraged to contact or investigators Second Sight at

In an official statement, the Post Office said: “Post Office Limited is concerned to hear about, and is determined to thoroughly and even-handedly investigate, cases where there have been persistent assertions that the Horizon system may be the source of unresolved shortages.”

Former postmaster Lee Castleton, who was suspended by the Post Office and ended up owing over £300,000 in alleged cash shortfalls and legal bills following a dispute over balances in his Horizon system, said: “Finally, we are getting somewhere.”