The Archbishops of Canterbury and York have called for a 'radical new Christian inclusion' towards gay couples in the Church of England after its ruling body voted down a report maintaining a conservative line on sexuality.

In the strongest hint yet of a change in Church policy they called for a new teaching document on sex and marriage that will be based on 'a proper 21st century understanding of being human and of being sexual'.

A joint letter was sent to all members of the CofE's general synod hours after the biannual parliament closed its sitting in London on Thursday. 

The archbishops wrote: 'The way forward needs to be about love, joy and celebration of our common humanity; of our creation in the image of God, of our belonging to Christ – all of us, without exception, without exclusion.'

Every bishop will meet with synod members under their authority 'to establish clearly the desires of every member of Synod for the way forward'.

It comes after the bishops suffered an unprecedented defeat when clergy threw out a report on sexuality that kept the Church's traditional line that marriage is between one man and one woman.

Although passed by the majority of synod members a technicality meant the body voted in its three separate houses – the laity, clergy and bishops – with the clergy voting it down by 100 to 93.

The archbishops' letter is in response to the setback and looks to address criticisms raised by a number of LGBT campaigners within the Church that they were treated as case studies and not people.

'In these discussions no person is a problem, or an issue,' the archbishops write. 'People are made in the image of God. All of us, without exception, are loved and called in Christ. There are no 'problems', there are simply people called to redeemed humanity in Christ.'

They called for a solution that was 'founded in Scripture, in reason, in tradition, in theology and the Christian faith as the Church of England has received it; it must be based on good, healthy, flourishing relationships, and in a proper 21st century understanding of being human and of being sexual.

'We need to work together – not just the bishops but the whole Church, not excluding anyone – to move forward with confidence.'

This is the full text of their letter:

Dear sisters and brothers in Christ,

Following the vote in General Synod not to take note of the paper on Marriage and Same Sex Relationships after the Shared Conversations (GS 2055) we are writing to set out the way forward in the next few months.

First, we want to be clear about some underlying principles. In these discussions no person is a problem, or an issue. People are made in the image of God. All of us, without exception, are loved and called in Christ. There are no 'problems', there are simply people called to redeemed humanity in Christ.

How we deal with the real and profound disagreement - put so passionately and so clearly by many at the debate - is the challenge we face as people who all belong to Christ.

To deal with that disagreement and to find ways forward, we need a radical new Christian inclusion in the Church. This must be founded in scripture, in reason, in tradition, in theology and the Christian faith as the Church of England has received it; it must be based on good, healthy, flourishing relationships, and in a proper 21st century understanding of being human and of being sexual.

We need to work together – not just the bishops but the whole Church, not excluding anyone – to move forward with confidence.

The way forward needs to be about love, joy and celebration of our common humanity; of our creation in the image of God, of our belonging to Christ – all of us, without exception, without exclusion.

Nevertheless while the principles are straightforward, putting them into practice, as we all know, is not, given the deep disagreements among us.

We are therefore asking first for every Diocesan Bishop to meet with their General Synod members for an extended conversation in order to establish clearly the desires of every member of Synod for the way forward.

As Archbishops we will be establishing a Pastoral Oversight group led by the Bishop of Newcastle, with the task of supporting and advising Dioceses on pastoral actions with regard to our current pastoral approach to human sexuality. The group will be inclusive, and will seek to discern the development of pastoral practices, within current arrangements.

Secondly, we, with others, will be formulating proposals for the May House of Bishops for a large scale teaching document around the subject of human sexuality. In an episcopal church a principal responsibility of Bishops is the teaching ministry of the church, and the guarding of the deposit of faith that we have all inherited. The teaching document must thus ultimately come from the Bishops. However, all episcopal ministry must be exercised with all the people of God, lay and ordained, and thus our proposals will ensure a wide ranging and fully inclusive approach, both in subject matter and in those who work on it.

We will also be suggesting to the Business Committee a debate in general terms on the issues of marriage and human sexuality. We wish to give the General Synod an opportunity to consider together those things we do affirm.

In the meantime, we commend to your prayers our common concern for every member of this church, of all views, and most especially our concern for the mission of God to which we are called by the Father, for which we are made ready by the Son, and in which we are equipped by the Holy Spirit.