Dr Rowan Williams said the "comforts and luxuries" we take for granted could not be sustained for ever and prophesied that civilisation would collapse one day.

We face a culture in which thoughts of death are "too painful to manage", he told worshippers at Canterbury Cathedral.

Dr Williams lightened the sermon's sombre tone by reminding people of Christianity's Easter message that death will be overcome.

But he said death was the end "in an important sense" and urged Christians to prepare for it by constantly striving to let go of "selfish, controlling, greedy habits".

The Archbishop went on: "We face a culture in which the thought of death is too painful to manage.

"Individuals live in anxious and acquisitive ways, seizing what they can to provide a security that is bound to dissolve, because they are going to die.

"Societies or nations do the same. Whether it is the individual grabbing the things of this world in just the repetitive, frustrating sameness that we have seen to be already in fact the mark of an inner deadness, or the greed of societies that assume there will always be enough to meet their desires - enough oil, enough power, enough territory - the same fantasy is at work.

"We shan't really die. We as individuals can't contemplate an end to our acquiring, and we as a culture can't imagine that this civilisation, like all others, will collapse and that what we take for granted about our comforts and luxuries simply can't be sustained indefinitely.

"To all this, the Church says, sombrely, don't be deceived: night must fall."