POST OFFICE documents containing “utterly abhorrent” racist terms to describe wrongfully convicted sub-postmasters were used internally and updated as recently as 2013, according to an internal investigation.

The company launched the probe last year after documents obtained by Horizon scandal campaigners found fraud investigators were asked to group suspects based on racial features.

Between 2000 and 2015, more than 700 sub-postmasters were prosecuted based on information from Fujitsu’s faulty Horizon accounting system used in Post Offices.