Start of the fiscal year?
If new bodies are being created, or old ones abolished or merged, then perhaps using this date makes sure everybody has a financial clean sheat.
I'm still looking for the April Fool stories in the papers as (with the exception of 'Fred Goodwin Returns Pension') it's hard to tell fantasy from reality these days.
The Independent has one about Miss Universe on a tour of Guantanamo Bay on page 3, which I'm worried may be real.
Well, that's obviously true... ;)
My mental image of a Miss Universe involves a blob with a couple of tentacles. A tour of Gitmo by such a creature may be exactly what the authorities there have in mind.
The wikipedia entries are already up proclaiming "It was established in April 2009" for the various new authorities !!!
Yes, they put quite a lot of effort into getting maps and copy ready to switch into place...