A bitter feud between two groups both dedicated to protecting the future of Putney Common has escalated over the sale of land for £350,000 — £1.5m less than its alleged correct value.

Friends of Putney Common group is demanding that Wimbledon and Putney Common Conservators (WPCC) fight to recuperate this money after allegedly underselling access rights on Putney Common.

The group has launched a petition demanding that Prue Whyte, chairwoman of the WPCC takes a series of actions including the launching of a legal review into the deal.

The petition also calls on Ms Whyte to suspend three WPCC Conservators and groups’ Chief Executive.

Wandsworth Council bought permission from the conservators to build a road across the common to the former Putney Hospital site — which is now being turned into a primary school and 24 luxury flats — for £350,000 in February 2012.

The WPCC’s former committee faced calls to admit breaching the Charities Act 2011 after a qualified surveyor’s report by Montagu Evans LLP put the land’s 2012 value at £1.9m — £1.55m more than the £350,000 for which it was sold to the council.

The charity’s right to sell off access to the land, protected as public space under the Wimbledon and Putney Commons Act 1871, was upheld in a Judicial Review in 2014 following an appeal launched by the Friends of Putney Common. In 2015 the Charity Commission was called in to investigate the case. It subsequently issued the WPCC with a series of recommendations in October, though the commission is still working with the conservators on the case.

A spokesman from The Charity Commission said: “We have serious regulatory concerns regarding the charity and is engaging with the charity’s trustees. As our engagement is ongoing we cannot comment further.”

Nick Evans, spokesman for Friends of Putney Common, said the petition was organised “out of exasperation”.

Within the petition, the Friends of Putney Commons has made a series of demands on the Trustee’s of the WPCC, including admitting it undersold the land as part of the easement agreement with Wandsworth Council, and engaging solicitors to begin work to try and recoup the shortfall.

The petition also calls for the suspension of the chief executive of the charity, Simon Lee, as well as three other conservators who were involved in the 2014 deal.

No one from the WPCC could be reached for a comment but a statement released in July said: “The Board continues to work with its legal advisors Charles Russell Speechlys on the implementation of the Charity Commission’s October 2015 Formal Action Plan.

“Following the update, given by the chairman at the Annual Open Meeting, the Board at its meeting on July 11, approved a process for selecting and appointing a surveyor to carry out the retrospective valuation.

“It is expected that, following a short-listing and interview process, the successful firm will be appointed in during September 2016.”