But set against that obligation is the resentment and ill-grace it generates. So try as the religious affairs department of the BBC and the small number of like-minded independent producers might to make material that stands on its own merits, they find it automatically relegated to graveyard slots - usually on a Sunday, precisely when the natural audience for such programmes is on its knees in church.
The religious programme makers have tried every trick to break free of the stereotype that regards all their output as variations on a theme of Songs of Praise. Documentary and discussion strands such as Everyman, Heart of the Matter and Channel 4's Witness take their specialist area into broader pastures with wider ethical resonances, while BBC1's FutureWatch, presented by Michael Buerk, linked religion with science and embraced an X-Files techno-obsessiveness.
But most effort is currently being directed towards making religion into light entertainment. So in September, The Heaven and Earth Show will become a feature on BBC1 on Sunday mornings until Advent. There's a bit of cooking with Rabbi Lionel Blue and Antony Worrall Thompson dishing up "soul food". There's a smattering of interviews on faith and motivation with household names such as Jo Brand, Uri Geller and John Cleese carried out by Catrina Skepper, one-time star of the Cadbury's Flake commercials. There's debate and news, plus the show's equivalent of the novelty singing nun - Sister Wendy Beckett musing on another old master. And playing Richard and Judy on this live Sunday morning hybrid are Simon Biagi, better known for his skills with a paintbrush in Real Rooms, and Amanda Reddington, once of GMTV.
"We represent a definite gear change for religious television," says series producer, Chris Loughlin. "Too much programming is directed towards those who are conventionally religious. We want to appeal to those with nothing more than an underlying feeling that there is something more to life than meets the eye. And we don't want to be taking our agenda from "church" news or churchy topics. That's being done well enough elsewhere. We want to look at the big questions of life as discussed by people everywhere and present them in a way that is not an objective examination, but a heated, participatory debate."
In such a catch-all formula, The Heaven and Earth Show's debt to day- time television is obvious. But there are signs that Loughlin may also have borrowed from the BBC's youngest terrestrial rival, Channel 5. In its first year school report, produced by the Independent Television Commission back in May, Channel 5 got top marks for news, children's programmes and religion. In this last category, the network's output, made by the experienced documentary maker, Roger "Death on the Rock" Bolton, was praised as pacy, fresh and full of vitality despite, as the ITC bluntly put it, "a lack of financial resources".
Over at the BBC, there is more money and so some of Channel 5's bright but underfunded ideas - such as My Sunday, the weekly celebrity "me and my God" slot, or Crossfire, the phone-in debate on moral matters - have been upgraded and added into the mix at The Heaven and Earth Show. More interestingly, Channel 5 has shown that such material can not only win plaudits but, especially in the case of its Christian rock music programme, The Alpha Zone, substantial audiences. Despite being broadcast on a Sunday morning, this show, presented by Jennifer Hughes, regularly notched up one of Channel 5's higher viewing and audience-share figures.
Loughlin is coy about acknowledging any direct debt, but admits to a wider link. "While other channels have been branching out in their treatment of religion for some time," he admits, "at the BBC we have kept within rather narrow confines."
Channel 5 certainly has demonstrated that with fresh input and an unashamed avowal of belief, religious programmes can make an impact with audiences. Whether The Heaven and Earth Show goes one step further and proves that religion can make good light entertainment remains to be seen. While there have been previous successes, such as the BBC's award-winning Heart and Soul in 1996, there have been many more failures, several associated with presenters with a good deal more experience and public profile than the likes of Biagi, Reddington and Skepper.
There was BBC's recent and much-panned It's Later Than You Think, a late- night Sunday series presented by Annabel Giles and Robert Elms. With guests such as Barbara Windsor, Mandy Smith and Jeremy Beadle, it struggled to give religion and ethics a look-in amidst a tired cocktail of comedy and topical debate. And ITV has in the past tried giving Gloria Hunniford, Sue Cook and Melvyn Bragg what were in effect chat shows but with a religious dimension.
It now, however, appears to be veering back towards a more high-brow product with the announcement last week that Bragg is to front Christian Millennium, a major new end-of-the century series which will follow 2000 years of church history in 20 hour-long episodes of reports and studio debate. Having almost single-handedly revived science as a fashionable subject on the airwaves, Bragg now seems set to work his particular brand of magic with religion.
Some insiders at the BBC, though, detect more sinister motivations in the rush to use the religious affairs department's budget to make programmes that dilute their special mandate with all-singing, all-dancing concepts that arguably belong elsewhere in the corporation. There is talk of plans to cut back religion to a few core areas - notably worship programmes in the Songs of Praise mould for radio and TV - and move the rest of the department's current output into the wholly secular arts and entertainment empire, based, like religion, at BBC Manchester. In this scenario, initiatives such as The Heaven and Earth Show take on the air of manoeuvres in a forthcoming take-over battle.