Priests claiming to be modern-day Martin Luthers have pinned a declaration to St Paul's Cathedral's doors warning the Church of England is 'corrupt' and in 'crisis' because of its softening stance on same-sex relationships.

In a symbolic act on the 500^th anniversary of the Protestant Reformation, a group of vicars posted the Southwark Declaration – a statement affirming conservative Anglican theology – to the doors of St Paul's Cathedral and Southwark Cathedral on Tuesday night.

The document, which has been signed by more than 60 priests and was first published in 2015, calls on bishops 'to regain the confidence of Bible believing Anglicans' in order 'to avoid a rupture in the church'.

They write: '500 years ago Martin Luther 95 Theses to a church door in Germany. He did it because the church had become corrupt. Today a Declaration is being fixed to a cathedral door here in England because the Established Church in our land is becoming corrupt.'

The document warns 'practice on the ground has already changed' in reference to allowing church leaders to be in committed same-sex relationships and warned it was 'weakening and destroying the church'.

The actual declaration contains five 'affirmations' surrounding conservative theology.

It comes as the Archbishop of Canterbury urged the Church to undergo another Reformation if it is to flourish amid 'political pressures' and 'the ferocity of sinful power-seeking' today.

Warning against using the Bible to 'serve politics or causes', Justin Welby used the 500th anniversary of the Protestant Reformation to call the global church to unite around fighting inequality and combating materialism.

'Today the gospel speaks to the inequalities of a 21st century world of inequality: of refugees and human trafficking; human arrogance and materialism; in the use of technology as a saviour, rather than as a gift,' he told hundreds of church leaders from around the world, including the heads of the English and Welsh Catholic Church and the Lutheran Church of Great Britain.

'Our speaking and living of the gospel must, like Martin Luther, be speaking to our world as it is,' he said at the Reformation's 500th anniversary service at Westminster Abbey on Tuesday.