ST PAUL's mission strategy focused on reaching cities first, which, in turn, spread to surrounding areas. Two hundred and fifty years ago, five per cent of the world's population lived in cities. Now it is 50 per cent.

This trend is largely reflected in the UK. People are moving to cities faster than the Church can keep up.

Cities create much of our culture, produce much of our innovation, and contain most of our people. They especially attract younger people and the poor. They are full of diversity and dynamism.

Yet cities are disproportionately under-represented in terms of ministry.

Cities need lots of different kinds of churches in order to flourish: large churches that can resource wider ministries, smaller churches that can go local and deep, and everything in between. The churches in a city are healthy when each one knows its own unique calling, when none is threatened by others, and when each one recognises the part it plays in the wider Church within that city.

CITIES are particularly in need of larger city-centre churches that can fulfil a resourcing function. Typically, such a church will draw people from across the city, and will have both a godly vision of the impact it might have, and the practical abilities to make that happen.

If positioned right, such a ministry can release a huge blessing to mission in a city as a whole. A big vision is needed for this to happen, one based on blessing the city rather than the church, simply getting bigger for its own sake. Everyone needs to know that this is the deal.

It's not a question of trying to reach the city on its own. Not even the biggest church can do this. But they can use their capability to energise a vision that other churches can get behind.

Resource churches do this in five ways:

1. Supporting bishops: Bishops have to take a wide view of the city. The resource church should be asking "How can we help you to achieve your vision?" In turn, the bishop could be giving permission and encouraging the city-wide vision and mission of that church.

2. Planting churches: Larger churches must get good at planting other churches that will multiply good practice and mission across a city, working with the bishop and with other congregations. Experience suggests that churches that plant attract leaders and members who themselves want to plant, and this helps those whom they send. Strategic planting with other churches and denominations should also evolve, as parts of the city in greatest need begin to be targeted for resourcing.

3. Releasing resources: Larger churches are more able to support staff who develop specialisms and resources. If these are focused on the needs of the city, and not just the needs of that church, it can enable many other churches to get involved, using and developing these resources. Examples include promoting marriage and family life, debt advice, caring for ex-offenders, and evangelism courses.

4. Sending teams: Ministry teams from resource churches can visit other churches to help run courses, lead worship, and give testimonies and talks. For churches that are called, for example, to highly contextual mission, this can be an enormous blessing, and encourages mutuality and reciprocity.

5. Developing leaders: Larger churches need more leaders, and are well placed to develop leadership-training programmes. These need to be aimed at raising up leaders to resource and equip the whole city. With a longer view, leaders of different disciplines can be developed for church planting into specific contexts: cross-cultural leadership in areas of different ethnicity, for example.

FOR all this to work, the larger, city-centre churches must embody some core values. These include:

• generosity: giving away what we have been given;

• partnership: working with others to reach our city;

• audacity: having the vision to transform the structures and communities, and capture the imagination of the city;

• humility: to serve the city and its churches.

SO HOW could this happen? Thinking of a larger city-centre church, the diocesan bishop could begin to ask how it could resource the city. Could it help to catalyse mission across the city as a whole? In its turn, the resource church could begin to ask how it could work collaboratively with the bishop.

If the city does not contain a resource church like this, the bishop and a group from the city's churches might work together to encourage one to be established. The leadership and resources required to plant a city-centre resource church are immense, and require help from outside the city as well as inside. But the fruit of such an invitation could transform mission to the city.

The Revd Ric Thorpe is Rector of St Paul's, Shadwell, London, planted by Holy Trinity, Brompton, in 2005. He has gone on to plant other Anglican churches within Tower Hamlets. He is the Bishop of London's adviser for church planting, Tutor in Church Planting at St Mellitus College, and Co-ordinator of the HTB Network.