Gay weddings in British churches may be legalised for the first time next week with the Scottish Episcopal Church (SEC) likely to change their definition of marriage.

In a move that will further emphasise divisions in the global Anglican church, Scottish bishops will recommend that priests be allowed to preside over same-sex marriages.

The major change in teaching is expected to pass after six of the seven local diocesan synods agreed to the proposal. The change also includes measures to 'protect' more conservative parishes that do not want to marry same-sex couples.

The SEC's general synod will be asked at its meeting on June 8-10 to pass a motion that removes the understanding of marriage as 'a physical, spiritual and mystical union of one man and one woman'.

The teaching will read: 'In the light of the fact that there are differing understandings of the nature of marriage in this Church, no cleric of this Church shall be obliged to conduct any marriage against their conscience.'

The motion must pass by a two-thirds majority in all three sections of the synod – bishops, clergy and laity – and insiders suggest this is likely to happen.

One senior source is quoted in The Herald as saying 'given what happened last year and with the diocese, people are expecting it to go through'.

The repercussions of the move are likely to be significant with traditionalists already lining up to take action.

GAFCON, a grouping of largely African and American conservative church leaders, are promising to plant a 'missionary bishop' to provide 'alternative oversight' for conservative parishes who no longer feel able to pledge allegiance to their local bishop.

In a communiqué announcing its decision, the group said: 'Of immediate concern is the reality that the Scottish Episcopal Church is likely to formalise its rejection of Jesus' teaching on marriage. If this were to happen, faithful Anglicans in Scotland will need appropriate pastoral care.'

If carried out, these threats would in practice see a split in the Church. One set of bishops would oversee the majority of Episcopal churches. Another set of bishops would effectively oversee a separate church made up of a minority of dissenters claiming the mainstream church had abandoned 'authentic' Anglicanism and the 'unchanging, transforming Gospel'.

Other than the local fissure, the move may also provoke a reaction from the Archbishop of Canterbury, who threatened 'consequences' for the SEC if they legalised same-sex marriage.

Justin Welby does not have official jurisdiction over the Scottish church, but as head of the worldwide Anglican Communion, of which the SEC is a part, he is seen as 'first among equals' when it comes to leadership.

In an attempt to hold the Communion together, The Episcopal Church TEC in the US were issued the same 'consequences' at a meeting of global Anglican leaders last January.

That led to TEC leaders removed from decision making at official Anglican meetings.

However conservatives are not satisfied and claim the consequences have not been fully implemented.

Despite attempts to heal the wounds since last January, a similar compromise agreement is unlikely this time and traditionalists will either insist on a proper rebuke to the Scottish bishops or they will walk away.

However this threat is equally unlikely to sway Scottish bishops. Warned of the consequences last year, the head Scottish bishops, Most Rev David Chillingworth, Primus of the SEC, said we 'will not change what we do'.

He added: 'Maybe it is a price worth paying for the ultimate healing of the Communion.'

A result is expected next Thursday afternoon.