Justin Welby has become the first Archbishop of Canterbury to interview a pope in a symbol of the warm relationship shared by the two Church leaders. 

In a significant moment for relations between the Anglican and Catholic Church, the interview was recorded on the Archbishop's mobile phone during a recent meeting in Rome.

The recording was made for Thy Kingdom Come, a global movement of prayer between Ascension and Pentecost on June 9, and will be played at a major rally of Christians taking place in Trafalgar Square on Pentecost.

In a clip published in The Times and to Twitter, Archbishop Welby described Pope Francis as "extraordinary" and told people to listen carefully to the "utterly inspiring" message from him.

The mutual affection was apparent as the Pope in turn referred to the Archbishop as his "brother". 

In the message, the Pope urged Christians of all denominations to pray for the Holy Spirit to come. 

"Come Holy Spirit, this is the cry of all Christians on this day of Pentecost.  Come Holy Spirit, the promise of the Father, the promise of Jesus that the Holy Spirit might enlarge and widen our hearts," the Pope said. 

He continued: "We all have a problem and that is that our hearts tend to shrink, becoming smaller and closed." 

He said the problem of closed-heartedness could not be solved by individuals but only by the Holy Spirit at work in them. 

The second prayer was for God's kingdom to come, he said, adding that Catholics "want to tell you that we walk alongside you in this prayer, thy kingdom come."