IN HIS new book On Rock or Sand, the Archbishop of York, Dr Sentamu, has been joined by the Archbishop of Canterbury in drawing attention to the growing gap between rich and poor. They urge that this issue must be at the forefront of attention in the run-up to the General Election.

Most Christians will be pleased with this move, especially those who are involved in the growing number of foodbanks. As churches up and down the country host hustings, and ply potential MPs with searching questions in relation to growing levels of poverty, we must, however, also demonstrate a similar passion for justice for younger and future generations.

It is cheap grace to lobby for policies that are sympathetic to the needs of the poor, but which serve to add to the burden of younger and future generations. For example, over the past 20 years, the cost of improving infrastructure - whether transport, schools, or hospitals - has been "kicked down the road" as a result of the Public Finance Initiative (PFI). Governments of both Left and Right have initiated almost 900 PFI contracts, which will bequeath to future generations a debt of £240 billion.

With the British national debt close to £4.8 trillion, those who would make a virtue of austerity easily seize the moral high ground, by insisting that the best way to help those yet to be born is not to saddle them with a massive national debt. Any Christian commentary that proclaims justice for the poor has to address this perpetual inclination to shift the obligations of current citizens on to the backs of future generations as yet unborn.

Those who make a virtue of debt-reduction are, to an extent, justified; but the risk is that reduction serves to turn the poor of today and the poor of the future into rivals.

We know very clearly that the hardship associated with austerity is disproportionately borne by those who are poor. It is, however, possible to square this unholy circle, and this insight comes from a surprising direction.

The First Church Estates Commissioner, Andreas Whittam Smith, will present a paper, Church Commissioners' Funds and Inter-Generational Equity, at the February meeting of General Synod. He lifts the lid on the naïve and uncontrolled financial liberality of the Church Commissioners in the 1980s and '90s.

For those of us with long memories, the first hint of financial disaster at the Commissioners was their reneging on the commitment to give £1 million for each of 18 years to the Church Urban Fund, a commitment not reinstated when finances returned to an even keel - evidence again that it is invariably the poor who take the biggest hit from financial misadventures.

In his paper, Mr Whittam Smith clearly and wisely articulates the conditions in which it is legitimate to "over-distribute" monies, even if this is at a cost to future generations. He describes the possibility of "bad" over-distribution, when money is squandered by the "pull of the now"; but there can also be "good" over-distribution, when spending is undertaken with clear purpose, supported by evidence of effectiveness; and ventures are fully costed, openly monitored and evaluated and, in the longer term, may produce a positive financial out-turn. Mr Whittam Smith will, no doubt, tell the General Synod that it is possible to spend church assets wisely - i.e. to sell some of the family silver - without being irresponsible in relation to future generations. We can and must say likewise to those who, in the forthcoming General Election, wish to be our representatives.

For the sake of justice, however, both now and for future generations, we must also throw down further challenges to our politicians.

Democratic governments struggle to take account of long-term concerns, because to do so cuts across the interests and pleasures of those whose votes they would like to win. In speaking up for justice and compassion, both for now and for younger and future generations, we have to forgo self-interest.

This means a willingness to say Amen to the legitimacy of inheritance tax. It means a willingness to say Amen to the introduction of a land-value tax. (I pause here to ponder whether our land-rich Church would wriggle and resist such an imposition.) We have to own the distortion of our homes into repositories for landfill, housing the stuff that we persistently accumulate.

Jesus observed that the poor will always be with us. Perhaps he came to this conclusion having discerned the habits and inclinations of the secure and comfortable.

When making the case for the iniquity of poverty-level pay, people like me - and, most probably, people like you - have to be very cautious indeed; for, when we are tempted to get on our high horse and protest against the growing gap between rich and poor, we don't just risk being snared by the presumed virtue of austerity but, worse than this, we risk haemorrhaging integrity; because we ourselves are not altogether innocent in relation to the processes that make the poor poorer, both now and in the future.

Ann Morisy is an independent theologian. She is the author of Borrowing from the Future: A faith- based approach to intergenerational equity, published by Bloomsbury.