The moving sight of man and whale united in extremis in the shallows of the Thames was a reminder that, in our over-scrutinised and over-regulated world, Nature still possesses some fathomless mysteries. Leviathan's strange and forlorn visit to London was a moment of reality television that provoked only the finest emotions - pity and wonder, and finally sorrow - among thousands of onlookers.

Those who lined the Embankment to watch the whale's doomed journey maybe felt a genetic twinge of nostalgia, too. When we crawled out of the ocean those billions of years ago, the whale was among the mammals we left behind. The threat of its extinction still hangs heavily on the world's conscience. Perhaps we love whales because they do more than connect us to deep waters. In folklore, the majestic whale is wise and all-powerful. In the Old Testament book of Jonah, the authorised version's 'great fish' that swallows the prophet eventually tunes its radar to the right frequency, receives the word of God and, after a long weekend in the depths, saves the errant holy man by spewing him up on to dry land, whence he goes on to rescue the reprobates of Nineveh from the wrath of the Almighty.

Either way, we have obligations. Which makes it so tragic that this time London's efforts to repay an ancient debt failed.

© Guardian Newspapers Limited 2006

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