A senior HS2 executive has resigned following a critical report by the public spending watchdog.
Steve Allen said he was stepping down from his role as chief financial officer at HS2 Ltd after the National Audit Office (NAO) revealed in July that the firm agreed £1.76 million in unauthorised redundancy payments.
The NAO found that the company ignored orders from the Department for Transport that its redundancy scheme should be restricted to statutory levels.
Mr Allen will leave his post at the end of the financial year.
HS2 Ltd chief executive Mark Thurston claimed Mr Allen had been "absolutely critical" in identifying ways to rectify "a number of issues that needed to be addressed", including administration of redundancies.
He described his resignation as an "honourable decision".
Mr Allen, who joined HS2 Ltd from Transport for London in October 2015, said the HS2 executive and board were "misinformed about the status of critical approvals for redundancies".
Redundancy compensation worth one month's salary for every year's service was agreed with outgoing staff to coincide with HS2 Ltd moving its headquarters from London to Birmingham.
The statutory standard is roughly one week's pay per year depending on age and length of employment.
Some staff were even offered paid leave to top up their exit packages above the £95,000 civil service compensation scheme limit.
Phase 1 of the £55.7 billion high-speed railway will open between London and Birmingham in December 2026, with a second Y-shaped phase launching in two stages.
Phase 2a from the West Midlands to Crewe will begin in 2027, followed by Phase
2b from Crewe to Manchester, and Birmingham to Leeds, in 2033.