It had a fair amount of circulation at the time but reminded people of too many preposterous atrocity stories to get much credence.
I heard and discounted it for just that reason. It reminded me of reading about propaganda from past wars, such as the mythical bayoneting of French babies by German soldiers during WWI.
Overall, though, it seems that Knightly is of the mindset that it's never too late to emulate the late, unlamented Neville Chamberlain. "Peace in our time!", indeed.