On 24 August 2026, the Post Office finally signed contracts with all three suppliers meant to replace Fujitsu’s Horizon system, the software behind Britain’s most widespread miscarriage of justice. Accenture takes over day-to-day running of the current system and is building the new back end, OneView Commerce will supply new till software for branches, and Escher will supply the software configuring individual transactions. Getting all three suppliers under contract at once, after a legal challenge and six delays to the same signing, is a genuine achievement: for the first time since the programme began, Fujitsu’s exit has a complete supplier line-up rather than a plan on paper.
This Pre-Mortem asks the questions a post-mortem would ask, before failure is possible: what is being bet on, what single assumption could break it, what got decided before the safeguards existed, who carries the pager when it fails, and what proof would settle whether it worked. It is the diligence a troubled, high-stakes programme deserves before its next test, not after.
The Bet
The Post Office is betting that three specialist suppliers working in parallel succeed where the government’s own auditors said success was structurally unlikely. The Cabinet Office’s Infrastructure and Projects Authority, in a 2024 review that rated the programme’s delivery unachievable, also found the Post Office board “not sufficiently experienced in technical matters to take decisions and make judgements on risk,” even as the organisation cut the programme’s own staffing by 70% on a delivery timescale experts called unrealistic. The bill has since grown to £1.1 billion, more than six times the £180 million forecast when the project began in 2021. The August signings are the moment that bet stops being theoretical.
The Assumption
The load-bearing belief is that Fujitsu’s departure now has a fixed date attached to it. It does not. Fujitsu’s existing Horizon contract carries a built-in option that could extend the relationship into 2028, regardless of how quickly the new suppliers deliver. Nothing in the August signings closes that option or replaces it with a firmer commitment. A three-supplier replacement can succeed completely, on its own schedule, and still share Post Office counters with the system it was built to replace for longer than any public document currently commits to.
The Sequence
The signing due in June was delayed six times before it happened in August, as a mandatory standstill period, the window in which a losing bidder can contest a procurement decision, was repeatedly extended around the original £170 million till-software contract. The losing bidder was Escher. Rather than resolve matters through that same competitive process, the Post Office created a separate contract and, a procurement notice later confirmed, awarded it directly to Escher without any competitive tender, worth £14.4 million, on the grounds that Escher alone owns the software needed to configure branch transactions. The fix for one procurement problem arrived only after that problem had already delayed delivery by months.
The Pager
Post Office CEO Neil Brocklehurst put his name to the official announcement of the completed supplier line-up, calling it “another important step forward” and describing the replacement as “one of the most significant changes” the organisation is making. He is the named executive carrying the transformation as a whole. But no individual, at the Post Office or in government, has been publicly named as accountable for the sixfold growth in cost since 2021, or for the procurement correction that delayed signing by months. The £1.1 billion and the delay sit with “the programme,” a description that assigns responsibility to no one in particular.
The Proof
In February 2026, the government committed £483 million in fresh funding, nearly half a billion pounds over two years, to support the move away from Fujitsu. Six months later, the announcement of the completed supplier line-up commits to no completion date and no performance metric: it states only that work is underway to establish detailed plans, timelines and delivery arrangements for a system that will be configured, tested and introduced in phases. Half a billion pounds of fresh funding has bought a supplier line-up, not yet a date. Eighteen months from now is roughly the point by which a working phased rollout, or its continued absence, should be publicly visible.
Verdict
If the three suppliers deliver a working, fully configured system, and Fujitsu’s exit is fixed in writing rather than left to an option that can run into 2028, the sixfold cost growth and the months of delayed signing will read as the price of getting a uniquely fraught IT replacement right rather than fast. If the timeline slips again, or the Escher direct award turns out to be the first of several sole-source corrections, the programme built to end Britain’s most damaging IT scandal will have spent well over a billion pounds relearning the same lesson about unaccountable decision-making that caused it.