I should now change the name of the blog to "English Language Etiquette for Britons"

See this horrifying link:

http://www.dailymail.co.uk/news/article-2827798/Don-t-tune-good-grammar-says-BBC-Broadcaster-no-longer-bastion-correct-English-insider-admits.html

Language question for readers - answers please!

Can any of the many readers of this blog supply us all (comments for publication) with a clear definition between the two modal verbs: "lock up" and "lock down"?

It is clearly not the same as the difference between "shut up" and "shut down"; much less "cut up" and "cut down", or even "sit up" and "sit down", which is obvious. So what is it?

I look forward to publishing the answers, and being enlightened at the same time!