The case of the Preston Down Trust presents reassurance and a note of caution for other Christian churches in their dealings with the Charity Commission, according to a senior lawyer in a London based firm.

"The law is clear that sharing the Christian faith is charitable in its own right," said Stephanie Biden, a partner at Bates Wells Braithwaite.

The Preston Down Trust (PDT) is a group of Plymouth Brethren churches that applied and appealed to the Charity Commission for almost five years, in an effort to receive charitable status.

Their initial request was turned down in 2012 because to be a charity, the PTD churches needed to prove they were working for the "advancement of religion for public benefit".

The Charity Commission challenged the application because of serious concerns over PDT practices, including "shutting up", where members who decided to leave the church were shunned.

Official guidance says that when it comes to official charity status, "It would not be sufficient for any such organisation to show that it is established solely for the benefit of the followers or adherents of the religion."

It was the view of the Charity Commission in 2012 that this isolationist activity meant PDT could not be considered a charity that acted for the public benefit.

However, in mid-January 2014, the Charity Commission altered its decision and PDT was registered as an official charity, giving it access to benefits including various tax exemptions, access to gift aid funds, and lower business rates.

According to Ms Biden, this ruling should give other Christian charities confidence in dealing with the Charity Commission, a body she understands many churches regard as "an unsympathetic and perhaps secularist regulator".

In particular, she mentions "a paragraph detailing how the Preston Down Trust serves the public benefit through its evangelistic practices."

The Charity Commission decision said "[PTD] engages in street preaching to spread the word of God rather than as a means of proselytising. The distribution of religious publications and spreading the gospel is clearly charitable."

Despite noting that it is confusing that the Charity Commission distinguishes between "proselytising", and the church's work to "spread the word of God", Ms Biden is generally positive.

"The encouragement for churches and mission organisations shouldn't be missed. The secular regulator has formally acknowledged that a church is established for the public benefit, thanks in part to its work of 'spreading the gospel'," she said. 

However, she does pepper this enthusiasm with a note of caution, in pointing out that as a result of the ruling, more churches could find themselves having to implement policy according to Charity Commission wishes.

"The Charity Commission has always claimed not to be interested in churches' doctrines or practices. But in registering the Preston Down Trust the Commission has, perhaps unwittingly, become an arbiter of church practice," she said. 

"To be registered as a charity, the church was required to formalise its theology into a statement of its core doctrines and set out its approach to discipline in a legally binding document called 'faith in practice', agreeing to ensure it acts with more compassion than it has historically been.

"If the Preston Down Trust doesn't follow through on these commitments and operate consistently with these new statements of its doctrines and practices, the Charity Commission can – in theory – determine that the church is not a charity and direct that its property should be given to another similar charity.

"The great irony is that a separatist group like the Trust is now accountable to a secular regulator body for its Christian practices. The authoritative position the secular regulator has taken in this albeit unusual case may well cause unease amongst other churches."