“New handbook of pastoral Liturgy” Michael Perham, SPCK, 2000.

“Whether the term ‘president’ is used or not, every leader of worship needs to understand he the concept that lies behind it.  It applies not only to the eucharist, but equally to some services where the president will not be a priest, but a deacon, a reader, or another lay worship leader.  At its simplest it is about holding the congregation together.” P30.

Quoting from common worship “The president at Holy Communion (who, in accordance with the provisions of canon B12.. must be an episcopally ordained priest) expresses this ministry by saying the opening greeting, the absolution, the collect, the peace and the blessing.  The president must say the Eucharistic prayer, break the consecrated bread and receive the sacrament on every occasion” P31 [rest of quote unclear, it seems the president can delegate parts of the service to an “officially recognised person”,  but unclear if it means from the above parts like the collect, or ALL OTHER parts of the service.]

[Discussed how the president during the service needs to be freed from having to ‘worry about every little detail’ so that they have time not only to be speaking the parts of the worship, but also partaking of the worship] “The tradition of the church gives us a second, complementary role of leadership in the eucharist, that of the deacon.  Always part of the Roman Catholic liturgical provision for the Mass, it was mainly lost in the Church of England, so that even a minister in his [or her!] year as a deacon before ordination to the priesthood rarely exercised a specifically diaconal liturgical role.” P34

[Quoting from common worship’s note on Ministries] “In some traditions the ministry of the deacon at Holy Communion has included some of the following elements: the bringing in of the book of gospels, the invitation to confession, the reading of the gospel, the preaching of the sermon when licenced to do so, a part in the prayers of intercession, the preparation of the table and the gifts, a part in the distribution, the ablutions and the dismissal.” [He continues in his own words] “The list of ‘duties’ might have been expressed a little more broadly. ‘The deacon invites the congregation – to confess, to exchange the peace, to make an acclamation, etc.  The deacon gives practical instructions – about posture, page numbers, etc.” P 34-35.

“Behind this note lie to main assumptions about the deacon’s role.  The first is that it is a ministry that makes explicit the element of service that lies hidden in all ministries.  The deacon serves God in serving both the congregation and the president.  The members of the congregation are served in the way the deacon encourages them and helps them through the service.  All through the deacon is inviting them to do things, and making it easier for them to do so.  But the president is also served by being relieved of some tasks and assisted with other tasks to lighten the burden, and that is important if the president is to be set free to be at prayer.  Throughout the liturgy the deacon is holding up to the priest and to the people a model of service, a service that, though it is of service, is not of subservience.  It is properly described as a complimentary ministry. To the deacon is assigned the liturgy of the word. To the deacon is assigned the task of dismissing the assembly at the end.  It is a two-person leadership of worship, a kind of team ministry, but one in which the roles are clear.  The two are not co-presidents, competing for a role… the belong together, often they stand side by side , they support one another, so that first one, then the other may move back into prayer, and then come forward to lead.” P35 
[I LIKE this guy!]

Edit - I found out later that Michael at the time of writing was the Dean of Derby Cathedral - ironic when I have been advised (in not exact these terms) not to bother by an Ex-deacon now vicar as "Derby Diocese does not understand deacons"... one wonders if his words fell on deaf ears...