In a statement issued this evening, Dr Williams underlined the grave ethical questions posed by manufacture and use of such weapons:

"... these are still weapons that are intrinsically indiscriminate in their lethal effects and their long-term impact on a whole physical environment would be horrendous. Whilst there is evidently disagreement - among Christians as well as others - over whether the mere threat of use is morally acceptable, we should not lose sight of what the Government itself has called the 'terrifying power' of these weapons."

This alone ought to be encouragement for those whose consciences were disturbed by the Government's decision to replace Trident to ensure that they contributed to the debate. Other concerns, including legal and strategic considerations, needed to be carefully considered, even by those who were persuaded of the moral case for a nuclear deterrent.

It was essential, he said, that the issue was properly aired:

"The White Paper must not close down discussion. We need a genuine debate in which Christians, and others whose consciences are disturbed by these proposals, will want to play a full part."

"I am very glad that we now have the Government's White Paper on the updating of Trident available for discussion. This is a serious matter, which requires the widest possible public consultation. The Prime Minister accepted in his statement today in the House of Commons that there are perfectly respectable arguments against the judgements the Government has made and that he both understood them and appreciated their force.

It is essential that careful consideration be given to three distinct levels of concern about these proposals.

First and foremost is the moral dimension. The ethical questions around the manufacture and use of nuclear weapons are no less grave now than in the days of the Cold War. Then, as now, these are weapons that are intrinsically indiscriminate in their lethal effects and their long-term impact on a whole physical environment would be horrendous. While there is evidently disagreement - among Christians as well as others - over whether the mere threat of use is morally acceptable, we should not lose sight of what the Government itself has called the "terrifying power" of these weapons.

Second there is the legal dimension. The White Paper recognises quite explicitly the need to justify any programme of modernisation in the context of Britain's obligations under the various non-proliferation agreements to which it is committed. Is the proposed programme compatible with these obligations? And even if it is technically not in breach, what message does the programme give? Will it restrain or intensify proliferation elsewhere?

Thirdly, though this is not an area where religious commentators can claim any expertise, there is the issue of the tactical or strategic purpose of the programme. Many people who are not convinced by the moral arguments against renewing and improving Trident and who would be agnostic about the legal question would still be anxious about substantial expenditure on a weapons system that had no clear strategic pointing the present global context. They would be particularly unhappy about this against the background of reductions in the resourcing of conventional forces, given the current acute pressures on the Armed Services of the UK who are actively engaged in the containment of conflict in a number of settings across the world

Many will never be persuaded of the morality of a nuclear deterrent; many more will feel that the case needs to be very strongly made for a programme of modernisation at this point if we are to avoid the suspicion that this is about reinforcing national status, at a very high cost to our actual military and strategic commitments at the present moment.

The White Paper must not close down discussion. We need a genuine debate in which Christians, and others whose consciences are disturbed by these proposals, will want to play a full part."

© Rowan Williams 2006