In a highly critical report into the debacle over the Horizon IT software, Sir Wyn Williams, chair of the Post Office Horizon IT Inquiry, said the top management at the Post Office ‘maintained the fiction that its data was always accurate’.

In the first part of a multi tome inquiry report into the accounting scandal, Sir Wyn Williams highlighted the Post Office’s excuses that problems occurred because of ‘bugs, errors and defects’.

The faulty accounting software saw hundreds of sub postmasters taken to court by the Post Office and convicted for fraud, which was not their fault, but the Horizon system wrongly reconciled transactions, leading to losses.