Sky News has learnt that Steve Blair left the OS earlier this month, little more than two years after joining from the private sector.
A source suggested he had decided to step down after becoming disillusioned by the extent of the company's control within UK Government Investments (UKGI), the agency which oversees state-owned companies.
Mr Blair, a former executive at companies including e2v, a sensor manufacturer, and Spectris, a supplier of precision instruments, could not be contacted for comment about the circumstances surrounding his departure.
The OS has now asked its interim chairman, Stephen Lake, to take on the additional role of interim chief executive following Mr Blair's departure.
A spokesman for the company said that Mr Blair would be available to assist with the leadership transition until the end of the year.
The OS has become an increasingly prolific provider of geospatial data to the private sector amid rapid innovation in technology-led consumer services which require precise location information.
In a statement, an OS spokesman said Mr Lake was "an experienced business leader with a significant track record in developing profit with purpose businesses".
"Steve Blair leaves OS in an excellent position with a strong board and leadership team, dedicated staff and an ambitious strategy focusing on both [British] and international markets.
"Steve leaves OS after two successful and challenging years, which included the job of leading OS through the pandemic."
UKGI declined to comment.