Certain countries are dirty. I'd like to say that I live in a clean country but that's only relatively true. You need only glance at the contents of a Tube carriage to see what I mean. Or for that matter, what the tradesmen leave in my street. The only reason I think I live in a clean country is because we pay people to clean up. People are pigs.

If we are talking about the production, collection and destruction of single-purpose cutlery on flights, as opposed to the cost of supplying heavy steel reusable cutlery, with the considerable costs of cleaning , storing, distributing and carrying it (let alone replacing what's been nicked), the argument's already been made. It's cheaper and easier.

We can eschew the plastic cutlery (which I detest) and carry and burn the extra fuel for a decent knife and fork, burn the coal or gas to heat the water to clean them and pay for the odd sets that get 'lost'. And it won't make a blind bit of difference.