Glad to know I'm not gonna be thrown in jail for holding Bitcoins.
They wont through you in jail, but they'll be watching the exchanges and come down on you like a ton of bricks if you trade your coins for cash and don't pay taxes on it. I'd stick to face to face trades if you're selling a lot of coins. Or just pay your taxes
in actual fact they dont inspect or watch exchanges, they just look at your bank accounts for amounts over your tax free threshold. nothing has changed in the last few decades, this is how HMRC has always worked.
this is mainly done if they get a tip-off. government agencys work mainly retroactive in regards to general public. they only work pro-active inregards to people or communications that highlight valuable information.
Interesting, but are you sure this is the case? Sources etc? I know they don't have the resources to go after everyone who's diddling their taxes, but I wouldn’t be surprised if they went after a few big Bitcoin busts to put the fear out there.