Post Office Horizon IT scandal: the main milestones so far

Problems with the Horizon system may have been behind accusations of fraud against 150 sub-postmasters


The Post Office’s ‘Horizon’ IT system, introduced in 2005, has been tainted by scandal in recent years.

About 150 sub-postmasters (people who own and run post office branches) say they were wrongly accused of false accounting by the Post Office as a result of problems with the system. 43 received criminal convictions and a number went bankrupt as a result. The stress was even blamed for driving one sub-postmaster to suicide.

The sub-postmasters claim issues with Horizon caused losses in their post offices, and they were forced to make up the shortfalls from their own pockets despite the errors lying with the system.

MPs, journalists and campaigners have taken up their cause, arguing the sub-postmasters are the victims of a serious injustice. The Post Office has denied this and insisted Horizon is ‘effective and robust’, pointing to the fact about half a million people have used it.

However independent experts Second Sight found software bugs when they investigated the system in 2012, and said the cash shortfalls could have been caused by malicious software or faulty IT systems.

After news emerged this summer that the Post Office is set to replace the controversial Horizon system, here is a timeline of the saga so far.