If the UK government cared about trees,
They'd have banned import of ash trees in 2009 apparently, and not now when the latest disease has arrived.
http://www.bbc.co.uk/news/science-environment-20107186
"The Chalara fraxinea fungus, which causes Chalara dieback."
But they jump at the chance to ban imports when they hear that German hens are laying funny shaped eggs. (I made that one up.) It's species-ist discrimination - or arguably kingdom-ist.
I'd have told them that I was going to go over last June, bring back a bunch of infected trees, and plant them in undisclosed locations, if they didn't do something to stop me. And if I saw any whales along the way, I would infect them as well. They probably wouldn't get sick but Japanese people might not want to eat therm any more.
In fact, I ought to find out Japanese people's favourite tree and any diseases that it gets, and infect whales with the diseases. I think it may be cherry.