Post Office suspected of more injustices over Horizon pilot scheme

Exclusive: software believed to have resulted in prosecutions even before full system rollout in 1999

• What is the Post Office Horizon IT scandal all about?
• I got tarred overnight': how Post Office Horizon scandal turned victims' lives upside down

The Post Office is suspected of wrongly prosecuting dozens more operators who took part in a pilot scheme of the faulty Horizon system, the Guardian has been told.

Amid growing anger over the treatment of postmasters whose lives have been ruined in the scandal, Whitehall sources have confirmed that a precursor scheme was rolled out in 1995 and 1996 to hundreds of branches in north-east England.