Accounting giant Deloitte has been fined £6.05 million over its audits of transport operator Go-Ahead Group, after regulators found a 'highly concerning pattern of failure' that left millions of pounds of taxpayers' money at risk.
Britain's Financial Reporting Council announced the penalty on Thursday 8 October 2026, saying it related to Deloitte's audits of Go-Ahead's financial statements for the years between 2016 and 2020. The headline fine had been set at £11 million but was reduced to reflect Deloitte's 'exceptional cooperation' and admissions.
It is Deloitte's second-biggest fine from the accounting watchdog, after the £15 million penalty imposed in 2020 for 'serious and serial failures' in signing off the accounts of Autonomy, the software company founded by Mike Lynch.
The fine relates to overpayments made by the Department for Transport to one of Go-Ahead's subsidiaries, London & South Eastern Railway, under a rail franchise agreement. LSER retained the money and did not tell the Department for Transport, which only became aware in 2021 and took action to recover the overpayments.
The FRC said Deloitte had 'failed to challenge the wrongful retention by (Go-Ahead Group) of over £30 million of public money for an extended period'. The watchdog found 'numerous breaches' at group level and at each of the three subsidiaries it examined: London & South Eastern Railway, London & Birmingham Railway, and Go-Ahead Bayern.
Penrose Foss, the FRC's executive director of investigations and enforcement, said: 'These breaches show a highly concerning pattern of failure by Deloitte to apply sufficient scrutiny to decisions and actions by (Go-Ahead Group) which were clearly questionable.' She added that it was 'particularly troubling' that the failings put 'very large amounts of UK taxpayers' money at risk.
A Deloitte spokesperson said: 'We regret that aspects of our audit work did not meet the standards expected and have learned from this matter. We are committed to continuous improvement and the delivery of high quality audits.'
The scandal has deep roots. Go-Ahead was stripped of the Southeastern franchise in 2021 after the Department for Transport said it had 'deliberately concealed over £25 million of historic taxpayer funding relating to HS1, which should have been returned to the taxpayer'. The department fined the company £23.5 million, Go-Ahead's shares were suspended, and the company was delisted from the London Stock Exchange in 2022. The regulator accepted that Go-Ahead had already begun retaining the money before Deloitte took over as auditor in 2016, but said the firm could and should have done more to challenge it.