There is a danger that the stage has been reached when we automatically disbelieve the government when it warns of a great danger. I believe, for example, that climate change is a great danger. Quite a lot of my friends, however, are dubious partly because the government is pushing it.

Consider the really major government scares of the last few years – things which were supposed to result in the death of millions – which proved to be nothing like the threat alleged. SARS, avian flu and swine flu all come instantly to mind. And what about the most ramped threat of all, the War of Terror, said by Tony Blair to be an “existential threat” and by John Reid to be a threat “On the scale of World War 2”.

There is an absolutely clear history of governmental over-exaggeration of threat, but also that governments have no difficulty in finding backing for this fear-mongering from government scientists and both techincal and inter-governmental international bodies. There are always virologists, vulcanologists and security experts willing to go on TV and tell us we are all doomed (oh, and can they get a bigger research grant to combat the threat).

So when the government promotes a big threat, I am conditioned to scepticism, even before British Airways flew a jumbo jet around for hours yesterday with the Chief Exec on board (after similar incident free test flights by other European airlines).

It turns out that the repeatedly quoted occasion when a BA flight lost power in all four engines due to volcanic dust, was a case of flying right through the plume close to the volcano in Indonesia. When you think about it, the fact that you can do something as extreme as that and nobody be hurt, is comforting rather than worrying.

As for widely dispersed ash, I have been wondering how Indonesia and Hawaii and Sicily ever manage flights. Why was there not a massive whole continent air lockdown after the vastly greater ash flown out by Mount St Helens?

As a society we have become risk averse to an unrealistic degree. We seem to spend our lives in a permanent state of cringe. Perhaps the ash really is too dangerous: but I see no reason to automatically believe the government on the subject.