There are new calls for Catholic communion to be reviewed.

Professor Thomas O'Loughlin, a University of Nottingham theologian is calling for new and formal discussions in the Roman Catholic Church to review an ecclesiastical law that prevents Catholics sharing Holy Communion with other Christian groups. 

Currently Papal law dictates that non-Roman Catholic Christians, for example Anglicans, cannot take part in the Eucharist (sharing of the bread and wine) at a Catholic service and similarly it directs that Roman Catholics should not take Holy Communion in other Christian churches. 

Professor Thomas O'Loughlin told Premier: "What you actually have to do is you have to start thinking again, did Jesus want this to be a reward for having the right doctrine and belonging to the right church and having all the right things? Or, was this a way that Christians gather on their journey and they support one another, and its food for the journey?"

He told Premier what he would like to see happen: "I would like to see all Christians looking on their meals together as joining together to support one another and in union with Christ.

"Offering thanks to the Father and the food being their food for their journey, in which case anyone who needs, anyone who wants is welcome, for the simple reason that the mercy of God knows no limits. Therefore, equally if I go to another church, I'm joining with you, you're praising the Father. I should join with you and rejoice with you and eat and drink with you too."

O'Loughlin believes change is possible: "The Catholic Church began changing its understanding and moving away from that whole emphasis on what you got 60-years-ago. But, like all these things, its two steps forward and one step back and it's a slow process.

"Because most people still have a view that it's about what you get. So I think it can change, but it will only change when people do an awful lot of thinking and reflecting on what we're doing, how we celebrate, how we gather, how we pray and how we praise."

It has been an issue that has been discussed by theologians and Christians for hundreds of years as Joe Ronan from Catholic Voices told Premier: "I think over the years, we've tried to work through the theological differences, and they are still there. Pope Francis has said he is also interested in these theological differences and how we might approach them, but they are not easy things to deal with.

"Pope Francis has said you can't just deal with them overnight. They need a lot of thinking about and I think we're a long way from squaring that circle at the moment.

"I think to Catholics, it's very important that we do understand the fact that during the Eucharist, the bread and the wine doesn't stay bread and wine but it becomes the body and blood of Jesus Christ. 

"Now to share in that we hope that people would understand the same things; if you go into a restaurant you want to know, if you order something on the menu that it is what you think it is, not what other people think that it is. So it is important to us."

Professor Thomas O'Loughlin explores the issue further in his new book Eating Together, Becoming One.