David Chillingworth, Primus of the Scottish Episcopal Church, seems relaxed about the prospect of a 'cross-border intervention' on his flock.

'In some levels I am disappointed,' he said when asked about a conservative 'missionary' bishop planned in response to gay marriage being permitted by Scotland's Anglicans. 

Within minutes of the SEC's vote, the conservative grouping GAFCON announced Canon Andy Lines as a 'missionary bishop' to oversee traditionalist parishes who want to defect from the official Scottish Anglican church 

Chillingworth told Christian Today: 'I don't think it will make very much difference here. The congregations which we have which will be giving serious thought to their position within this Church following this vote will do that on their own and in context of our relationships here.'

But despite this apparently laid-back attitude, the decision by conservatives to make Lines a bishop has caused shockwaves around the Anglican Communion. 

The Archbishop of Canterbury rebuked the move, warning a 'missionary' bishop would 'carry no weight in the Church of England' and citing canons from Christianity's formative Council of Nicea in AD 325 to warn of the 'great disturbances and discords' it would cause.

The issue is likely to be discussed at the next meeting of global Anglican leaders in October.

Although Welby is clearly nervous by the overt challenge to his own authority and to the official Anglican structures, there are genuine questions as to what difference it will actually make.

Announcing the move, GAFCON's primates – leaders of Anglican Churches in Africa, South America and the US – said it was in response to their view that 'faithful Anglicans in Scotland will need appropriate pastoral care'.

But they add: 'In addition, within England there are churches that have, for reasons of conscience, been planted outside of the Church of England by the Anglican Mission in England (AMiE).

'These churches are growing, and are in need of episcopal leadership.'

So the missionary bishop is to provide leadership for 'faithful Anglicans' in Scotland, and Anglican churches 'outside the structures of any Anglican province, especially in Europe'.

Andy Lines will not therefore be offering oversight to official CofE churches.

The CofE has already made clear the simple fact that this would in any case be illegal.

When asked about the consecration by a South African bishop of another 'irregular' bishop, Rev Jonathan Pryke, in the parish of Jesmond, a spokesman for the Bishop of Newcastle said: 'No overseas bishop may exercise episcopal functions within the Church of England without the express permission of the Archbishop of the province and a commission from the Bishop of the diocese in which they wish to minister.'

The spokesman added: 'It is the clearly established law of the land that no one can exercise ministry in the Church of England without either holding office or having the permission of the diocesan bishop.'

A Canon lawyer told Christian Today that if a parish were to bring in Lines to fulfil a bishop's duties, such as confirmations, this would be in breach of Canon Law.

'Whilst the removal of the priest's licence would not be automatic, it is quite likely that he would be subject to a complaint under the Clergy Discipline Measures,' they said.

The same also seems to apply in Scotland with SEC law stating that no bishop 'shall interfere with the concerns of another diocese' and 'no bishop shall perform any episcopal function in any other diocese without the sanction, nor exercise any other ecclesiastical function against the will, expressed in writing, of the bishop thereof'.

It adds: 'The clergy of a diocese shall take no direction for their official conduct but from their own Bishop, except in the case of a lawful decision of the Episcopal Synod, or of the College of Bishops.'

It seems GAFCON intends to skirt the legal issues in Scotland by distinguishing between the 'episcopal' role of a bishop – such as carrying out ordinations and confirmations – and the 'pastoral' role of a bishop – which could simply mean meeting informally to offer support.

A GAFCON spokesman told Christian Today: 'The missionary bishop will only carry out episcopal functions in congregations that are outside the Church of England and the Scottish Episcopal Church if invited. There may be bishops who invite the GAFCON missionary bishop to perform episcopal acts to biblically faithful clergy and congregations within their structures.

'Across the provinces in the UK and Europe there are thousands of congregations, and scores of dioceses. The way each congregation practically relates to their diocese and bishop is not uniform. What would and would not be an appropriate pastoral response from the missionary bishop to an enquiry from a congregation in an existing province can only be evaluated on a case by case basis.'

The obvious legal challenges have not stopped a host of senior conservatives rushing to welcome the move.

Rod Thomas, appointed Bishop of Maidstone in 2015 to offer 'alternative oversight' for parishes with a conservative 'headship' view on the ordination of women, said he welcomes 'the steps that GAFCON (the global fellowship of orthodox Anglicans) is taking to support those who are seeking to stand firm by the Bible's teaching on marriage and sexual relationships, and wishes to assure Canon Andy Lines of my prayers as he becomes a missionary bishop'.

Director of traditionalist CofE grouping Reform, Susie Leafe, said: 'The appointment of Revd Canon Lines to this role will encourage faithful Anglicans in Scotland and across Europe to know they are not alone and give them confidence to proclaim the wonder of God's saving and transforming grace through Jesus Christ alone.'

But below the surface it seems the missionary bishop is primarily for those who have already left the Church of England and Scottish Episcopal Church, or who were never part of them.

Andy Lines will not be an alternative bishop for ordinations and confirmations in the CofE proper because that would be against Canon Law, which means it would be illegal in a secular sense as well. The Church of England is the established Church, which means its ecclesiastical laws have the status of secular laws. 

It is a reflection of a split that has already happened, rather than causing one.