Chris Packham is challenging the Archbishop of Canterbury, Justin Welby, to support rewilding across the Church of England’s vast estate.

The broadcaster is taking to the steps of St Paul’s Cathedral on Sunday, to call on the Church to commit to rewilding 30% of Church Commissioners – the Church’s investment arm – to rewild its extensive landholdings.

Packham, dressed in a medieval costume, will unveil a nine metre-long scroll, outlining why the organisation should rewild 30% of its 105,000-acre estate by 2030 in line with the UN’s Global Biodiversity Framework.

Almost 100 public figures have contributed to the scroll, which is called the “95 Wild Theses” as a twist on the original “95 Theses” – a document written and allegedly nailed to a church door by 16th century religious figure Martin Luther in opposition to what he saw as the Roman Catholic Church’s abuse and corruption.

Contributors include former archbishop of Canterbury Dr Rowan Williams, former housing secretary Michael Gove, actor Stephen Fry, former IPCC chair Sir Robert Watson, chef Hugh Fearnley-Whittingstall and former Green Party leader Caroline Lucas.

It comes as part of a wider rally on Sunday where environmental activists, families, artists and churchgoers plan to dress up and march from Tate Modern to St Paul’s Cathedral.

Environmental campaigners have claimed that the land owned by the Church Commissioners is largely used for intensive farming and has the lowest overall tree coverage of the UK’s top institutional landowners.

During his speech, Packham is expected to say: “The Archbishop of Canterbury Justin Welby and the Church’s wealthy investment arm – The Church Commissioners – are failing all things bright and beautiful.

“As one of the biggest institutional landowners in one of the world’s most nature-depleted countries, the Church should be a leader in restoring our precious wildlife.”

Mr Packham said the Archbishop and the Church Commissioners, including the Bishop of the Environment Graham Usher have declined campaigner’s attempts to discuss how they can rewild the estate.

“If they are willing to practise what they preach they could rewild just a third of their land, which would equate to an area 90 times the size of Hyde Park, and give British wildlife the salvation that it desperately needs,” he added.

Wild Card, the campaign group behind the event, said the 95 Wild Theses include a series of ecological, climatological and theological arguments, which will be delivered to the offices of the Church Commissioners and Lambeth Palace on Sunday afternoon.

Dr Williams said: “Letting the natural world be itself – not just a reserve bank for our convenience – is an act of grace, and one that we should be glad to embrace, because when the world around us flourishes, so do we.”

Meanwhile, Stephen Fry said: “The church commissioners have a wonderful opportunity to make so much of its unique landholding. The 30×30 plan is potent, achievable, manageable and hugely beneficial.”

The campaigners acknowledged that the Church of England has shown global leadership in supporting the UN climate goals by divesting from fossil fuels and its democratic body the General Synod passed a motion calling for action to increase biodiversity across the Church’s various landholdings earlier this year.

But they said it still lacks concrete and measurable targets for it’s single largest landholding – the land owned by the Commissioners.

Paul Jaffe, head of sustainability, real assets for the Church Commissioners, said: “While large-scale rewilding is not appropriate for our highly productive farmland, we are deeply committed to supporting nature through a range of initiatives.

“We focus on sustainable farming practices, collaborate with organisations like the RSPB and FWAG, and actively integrate biodiversity projects, such as woodland creation and wetland restoration, across our portfolio.

“Our approach ensures we balance food production with stewardship of the land, helping to safeguard nature for future generations.”

The organisation said it has a legal obligation under charity law to use its assets in a way that generates market returns.

It added that the entirety of its approximately 82,000-acre farmland portfolio is leased to farming tenants, many of whom are from are multi-generational farming families with long-term leases.

The Commissioners also said it is committed to implementing sustainable farming practices across its farmland portfolio, working with tenants and green groups to implement regenerative farming and support biodiversity.

Meanwhile, its 88,000-acre forest portfolio has been independently certified by the Forest Stewardship Council as adhering to strict environmental, social, and economic standards, it added.