Between 2000 and 2014, the Post Office prosecuted 736 sub-postmasters and sub-postmistresses - an average of one a week - based on information from a recently installed computer system called Horizon.

Some went to prison following convictions for false accounting and theft, many were financially ruined and have described being shunned by their communities. Some have since died.
After 20 years, campaigners won a legal battle to have their cases reconsidered, after claiming that the computer system was flawed.