Current and former postmasters who have incurred financial losses they believe are due to glitches in the Post Office's Horizon computer system are forming a pressure group to air their concerns.

Alan Bates, who was a postmaster in North Wales from 1998 to 2003, plans to hold a meeting in late October or early November for those affected to gather evidence and devise a structured way forward.

Dozens of postmasters have come forward to say that unexplained discrepancies on the Horizon system have led to financial shortfalls, loss of post office or even criminal prosecution (see Dear Jac).

The issue has been highlighted in an S4C documentary in Wales, and North Wales MP David Jones is pressing for a House of Commons debate on the issue.

The Post Office vehemently defends its continued use of the Horizon system. A spokesman said: "Our Horizon IT system, which operates across the Post Office network, is extremely robust and successfully records millions of transactions each day, and there is no evidence pointing to any fault with the technology.

"We would always look into issues raised by subpostmasters."

For more details about the meeting, contact Alan Bates on 0777 853 6886, or email