The Moderator is the chairman of the annual General Assembly, the governing body of the Church, which is the single largest Protestant denomination in Ireland. He is also the public face of Presbyterianism and is called upon to comment on major issues.

However, a Moderator does not have quite the same individual authority of a Church of Ireland or Roman Catholic Bishop in his own diocese - although these leaders are ultimately responsible to the laws of their own churches.

Even the election of a Moderator is something of a mystery to the public - including many Presbyterians.

Each February, representative clergy and laity from Ireland's 19 scattered presbyteries meet to nominate one of several candidates for election.

These people have been asked beforehand if they are happy to allow their names to go forward.

If there is a tie in the first round, a second vote takes place the same evening. This is a new departure, as previously a first-round tie led to a second election a few weeks later.

As soon as the successful candidate's name is known, there is a swift Press release announcing the news and a Press conference called for the next day.

For most ministers with little experience of media scrutiny, this is a daunting prospect. And because the term lasts for only a year, the Moderator is required to leave office at about the time as he is basically getting the hang of the job.

Many Presbyterians see this as a waste of time and experience, but it is unlikely that the General Assembly will change the rules.

A Moderator can take some initiatives, such as launching appeals for humanitarian and development aid, and make at least one major overseas visit. However, his power is limited by the General Assembly, which guards its authority jealously.

Some past Moderators, like the Very Rev Dr John Dunlop, have been politically adept at using the powers at their disposal, but most others in recent years have carried out largely ceremonial and significantly pastoral duties.

With the lessening of the Troubles, Presbyterian Moderators - like other church leaders - have been making fewer headlines.

All of this imposes even greater challenges for a new Moderator who wishes to make his mark on the Church and society during his year of office.

In the coming year, there will be particular challenges for the Rev Patton, including the Church's attitude to same-sex relationships, having to deal with significant commemorations, such as the signing of the Ulster Covenant by thousands of Presbyterians in 1912, and bringing the General Assembly meeting to Londonderry - the 2013 UK City of Culture.

Each new Moderator has a difficult role, as he tries to achieve a representative balance between the different wings of his church.

The outcome usually adds up to some kind of bland compromise and, unless a Moderator is determined to take a strong lead and to bring as much of the Church as he can with him, this state of affairs is likely to continue.

In the final analysis, most people have some idea of the identity of church leaders, such as the Roman Catholic Primate Cardinal Brady and the Anglican Primate Archbishop Alan Harper, who have been in their posts for years.

However, the public would be hard-pressed to remember the name of any of the recent Presbyterian Moderators - and that is not necessarily their own fault.

They have become largely public figureheads, while the real power rests with the General Assembly and its major committees, and this is unlikely to change in the foreseeable future.