Lee Castleton, one of the most high-profile victims of the Horizon IT scandal, has launched a £4.5 million lawsuit against the Post Office and Fujitsu, alleging malicious conduct, abuse of process, and conspiracy to pervert the course of justice.
The legal action, which represents the first individual claim of its kind against both organisations, was revealed through newly published court documents. The claim sets out forensically detailed losses and raises the prospect of a damaging court battle that could reshape accountability for one of the biggest miscarriages of justice in British legal history.
Mr Castleton was portrayed by actor Will Mellor in the ITV drama Mr Bates vs the Post Office and was awarded an OBE for services to justice earlier this year. Speaking to the BBC, he said: “It’s not about the money. What matters to me is that I get vindication from the court.”
Mr Castleton, a former sub-postmaster in Bridlington, East Yorkshire, was wrongly accused in 2004 of a £25,000 shortfall in his branch’s accounts due to errors in the Horizon IT system, developed by Fujitsu.
In 2007, after a two-year legal battle with the Post Office, Castleton was ordered to pay £321,000 in legal costs and was made bankrupt. He had defended himself in court after his legal insurance ran out. His was the only civil claim the Post Office ever brought against a sub-postmaster — a decision the official inquiry later heard was made to “set an example”and deter others from challenging the system.
Now, Castleton is seeking justice through the courts once again — this time on his terms.
In his civil claim, Castleton outlines both quantifiable financial losses and general damages, including:
£940,000 in past lost earnings
£864,000 in future loss of earnings
£933,000 in past pension losses
£133,000 in property-related losses
£232,000 in lost rental profits
£109,000 from the forced sale of his business
He is also seeking:
£30,000 for mental distress
£30,000 for stigma and reputational damage
£45,000 for harassment
£50,000 for maliciously causing his bankruptcy
His solicitor, Simon Goldberg of Simons Muirhead Burton, described the claim as “startling”, adding: “This is the first time forensic details of a sub-postmaster’s claim have been made public. The complexity and extent of the damages reflect the life-altering impact of what happened to Lee.”
Castleton’s legal team accuses the Post Office of abusing the legal process, arguing that the judgment made against him in 2007 was “obtained by fraud”. They further allege that the Post Office and Fujitsu conspired to withhold crucial evidence, including internal knowledge of bugs in the Horizon system and the existence of remote access by Fujitsu employees to sub-postmaster accounts — which undermined the integrity of transaction records.
The claim also references the role of Gareth Jenkins, a former Fujitsu engineer who gave evidence in many Horizon prosecutions. The Post Office failed to disclose in civil litigation that Jenkins had breached his duty as an expert witness — a revelation that has since become central to the scandal’s broader legal fallout.
Castleton argues that the 2019 group litigation settlement, in which he was one of the 555 claimants, does not cover his current claim, and that the Post Office again withheld material evidence that should have influenced the outcome of that case.
In addition to compensation, Castleton is seeking to have the civil judgement and bankruptcy order against him set aside. His lawyers allege that these legal actions — pursued while the Post Office was aware of flaws in its IT system — were unjust and malicious.
The Post Office declined to comment on the case specifically, citing ongoing legal proceedings, but said: “We recognise the devastating impact of the Horizon IT scandal on former postmasters like Mr Castleton. The Post Office today is committed to doing all we can to help those affected get closure.”
Fujitsu also declined to comment when approached by the BBC.
Mr Castleton has chosen not to engage with the government’s Horizon compensation scheme, stating that he has lost faith in the process and instead wishes to pursue full judicial vindication.
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Horizon victim Lee Castleton sues Post Office and Fujitsu for £4.5m in landmark legal claim