John Tizard is to step down as chair of the local infrastructure body Navca after just seven months in the role.
A statement from the charity, which supports third sector support organisations such as councils for voluntary service, said Tizard was leaving the position this week in order to "focus his energies on his role as a commentator, politician and campaigner, and to ensure that these activities do not create any conflict of interest for him as a trustee of Navca or for Navca as it delivers its core role on behalf of members".
Tizard, a former Labour councillor, was a Navca trustee and adviser for almost eight years before becoming the charity’s chair at its annual general meeting in December
The Navca statement said Tizard would step down from his role this week.
"John will continue to champion local social action and the role of local VCS infrastructure bodies in a variety of ways, whilst in future giving greater focus to his commentating, political and campaigning activities," it said.
"John has taken this decision to ensure that these activities do not conflict with nor detract from the work of Navca’s core role; and to enable him to be forthright and not constrained by his role as Navca chair."
Asked if there had been any tensions between Tizard and the executive or other board members, a Navca spokesman repeated the statement that he was stepping down to focus on being a commentator, politician and campaigner.
The spokesman was unable to provide further information about the process of recruiting a successor, how long this might take and whether an interim chair would be appointed in the meantime.
In the statement, Tizard said it had been a privilege to have been involved with Navca for almost nine years.
"Whilst I am sad to be standing down as chair, I believe that I will be able to offer more support and further challenge in other ways.
"Over the last six months, I have visited over 25 Navca members and met many others. Each time, I have consistently been impressed by their commitment, their impact and their willingness to change.
"I have come away from these visits further convinced of the need not only to argue the case for local infrastructure with still greater vigour, but also and more fundamentally to promote social justice and equality, and radically challenge the structural and policy barriers to equality, fairness and opportunity; and sometimes to challenge and nudge the sector too. I am absolutely of the view that the time for such action has never been greater than now.
"Accordingly, I plan to continue to pursue this agenda with added determination as a commentator and activist."
On behalf of the Navca board, Alison Semmence, the charity’s vice-chair, thanked Tizard for his service.
"During his involvement with Navca, John has maintained a resolute and relentless focus upon the interests of Navca’s members and the communities that they serve right across England," she said.
"We know members will be sorry to see him stand down, but we hope that they will fully understand and support his integrity and purpose in doing so.
"Indeed, we are in no doubt that, with his new focus, John will continue to support and complement Navca’s objectives, programmes and activities.
"We can assure all our members and sector partners that Navca has a clear vision for the future, a strong board and an excellent staff team.
"We are confident of Navca’s ability to thrive and build on the good work that has been done in recent years."