The UK Post Office lost £31 million ($39.43m) in 2023 to its failed cloud migration, reports The Stack.

Revealed in an annual report, the Post Office's total restructuring costs reached £38m ($48.3m), making the loss around 81 percent.

The report explains that: "In addition to the CGU (cash-generating units) assessment, a decision was made to discontinue an IT project that was part of a transformational program to move existing software onto cloud infrastructure. As a result, an additional impairment of £31 million (2022: £nil) was recognized due to the associated assets no longer having any economic benefit."

This news comes amidst a criminal investigation into the Post Office over potential "fraud offenses" committed during the Horizon IT scandal.

The scandal, recently brought back into public consciousness by ITV drama series Mr Bates vs the Post Office, is related to several prosecutions of postal workers between 1999 and 2015 due to its faulty Horizon accounting software that was delivered by ICL and then Fujitsu. Around 700 post office branch managers were prosecuted, and at least 93 have already been overturned. The Post Office has thus far paid out £86m ($109.4m) in compensation.

Despite the controversy, system errors, and test scripts being published to help "make improvements based on actual day-to-day issues Postmasters face when using Horizon" as recently as 2021, that same year Fujitsu won a £42 million extension to its contract.

This enabled Horizon to continue being used until 2024, though that extension did not reportedly include on-premises hosting, data center operations services, and central network services which would be replaced with a cloud hosting solution.

This was set to be provided by AWS and completed by 2023, though failed to happen.

The Post Office signed another Fujitsu Horizon extension in April 2023 for £16 million ($20.35m), and a £36 million ($45.8m) extension in November, stating that Horizon "is a highly complex platform, written in legacy versions of software languages and which incorporates five "systems" in one i.e. financial services, banking, government services, mails and retail… the inflexible nature of the construction of the architecture of "Horizon" itself makes technology change challenging."

The Horizon software will continue to be used by the Post Office, operated out of its two Belfast-based data centers, until at least the end of March 2025. In total, the Post Office has spent over £2.3 billion ($2.93bn) with Fujitsu for the platform.