SUDDENLY there is a new engagement with our economic environment on the part of those who speak for the Churches, which is also striking a chord with a wider public.

The Archbishop of Canterbury goes head to head with the chief executive of Wonga; the long struggle to get a credit union for the Church of England looks as if it might succeed; large audiences fill St Paul's Cathedral to debate "The City and the Common Good", and seminars to take the issues further are fully booked; the Bishop of Liverpool, the Rt Revd James Jones, finds no lack of willingness among senior figures in the financial world to face empathetic yet robust questioning in his three-part Radio 4 series, The Bishop and the Bankers ( Comment, 19 July; Radio, 2 August).

All this is very encouraging; and if the debate is more widely engaged in, and if, at a practical level, local churches can offer facilities and well- trained volunteers to extend the reach of credit unions into the fabric of communities (as is the case in other countries), it will be even better. We will need more of the probing of those in authority in the world of finance, of which the Archbishop's engagement and Bishop Jones's investigation are such valuable examples.

Already, however, some more difficult issues are coming over the horizon, and they are ones that will drive the Churches, if they are willing, into some more conflicted areas of political and economic discussion.

When the David of the credit-union movement confronts the Goliath of the payday lenders, they find - as the CEO of Wonga showed in conversation with the Archbishop - not the bared teeth of the threatened, but the warm embrace of someone who sees the credit-union movement not as subversive of the regime that profits from others' misery, but rather an extension of "consumer choice".

As with the department store that welcomes a competitor's arrival because it will serve to increase all-important footfall, so the moneylenders are wise enough to notice when the Church appears to give approval to the notion that the poor remain poor because they have not got enough choice about where to borrow.

CREDIT UNIONS are a hugely valuable asset: they invite members of a community - a "common bond" - into an environment where each can assist the other in ironing out the peaks and troughs that would be part of life in any economic system: you can save, and the money can be used to enable others to weather a crisis - the washing-machine breakdown, for example. Then the roles can reverse, as members' times change. All this can be done in an atmosphere of mutual responsibility that can take the fear out of money.

Credit unions can offer all this, and so they can be a real instrument of financial communion, of common life, a vital part of the Church's mission to foster community. That is why the demutualisation of building societies - the subversion of money from being an instrument of common life to its being a means to reproduce itself as just more money - was such a tragedy, one that makes the current encouragement of credit unions ironic. But, if credit unions are to do the task to which they are ideally suited, we need to be clear that there are some things that credit unions are not.

They are not a solution to poverty; and the means to build up a buffer against sudden crises is no answer to the increasing number of people living, by their own admission, near to the financial edge. They are no fix for those who borrow simply because there is too much week for the money that comes in, too little of it to deal with the regular outgoings of food, children's clothes, heat, light, and water.

Credit unions are not an adequate response to this Government's relentless drive towards increased inequality - if they were, they would not be so warmly welcomed by a Government that has assiduously punished the poor for being poor. The briefest examination of the statutory objects of credit unions makes it clear that they are for those who have, or can be sure of having, over their lifetime, an income stream that is assured and adequate.

WHEN Wonga and George Osborne praise the Churches for encouraging credit unions and "widening access to credit", it is easy to be seduced away from the radical criticism that is needed of what capitalism has allowed the banks to become. The Bishop and the Bankers started to take listeners back into that essential task.

But the real issue is not something as vague as "capitalism": it is what specifically money has been allowed to become: not a medium of common life, but a massive quantity of debt, created by banks for banks to profit from, and, in the process, a disaster waiting to happen.

Prophetic voices have been raised about this for decades, and continue to be. Rather than admit that the crisis that began in 2007-08 vindicated those warnings, the welcome to the Churches' practical action in encouraging mutual credit unions could allow us to forget the underlying issue of what happens when banks are allowed to make money out of making our money for us.

So it is good news that the Churches are showing real signs of refreshing their critical judgements about money, debt, usury, and all the other issues of economic justice about which the scriptures and the story of faith have so much to say. But we shall need to enter that arena aware that money itself is what is at stake. We should certainly tremble when the money-lenders speak well of us.

Dr Peter Selby is a former Bishop of Worcester.