I was there at the National Archives, yesterday (March 31st), when this new 'discovery' was announced. This story sounds generally plausible (certainly there was a lot of other wacky stuff that happened in this period) but the anouncement was carried off with such a light touch that I honestly don't know if it's a prank or not.

I can, however, verify one or two things:

Blue Peacock was -not- on display a the National Archives, as the Slashdot story suggests. There is, in fact, another thermo-nuclear bomb there.

I have not seen the documentation behind the chickens claim, although plausible looking documents were brandished at the audience. We were told that the discovery was 'too recent' for documents to have been coppied for us in time.

If this is a prank, several famous and important Cold War and Secret World historians have been taken in. Most of the people I spoke to were utterly convinced that Prof Hennesy was telling the truth.

The text reported to us was in just the right style to be a genuine document. On the other hand, Prof Hennessy and his team are the world's leading experts in this field, so you'd expect them to get it right.

I got the impression that this was not a fully fleshed-out plan, but an idea mooted by some engineer which rated a single paragraph in a much longer document.

If, indeed, this document has been shown around, that would mean that it is almost certainly genuine. As Prof Hennessy pointed out, why would the provide many pages of highly technical writing for such a joke? On the other hand, I have not seen these documents and have not spoken, personally, to anyone who has.

Either way, hats of to Petter Hennessy and the Secret State reserch team at Queen Mary.