I don't know about the heavy industrial side of things, but for lighter duty such as domestic and small commercial, I'd say that direct-burial SWA is far-and-away the most common method here (not counting homeowner specials such as flexible cords pulled through garden hose, etc. [Linked Image] ).

Most of you already know what SWA looks like, but just in case:

[Linked Image]

It's widely available in 2-, 3- and 4-core variants with conductor sizes from 1.5 sq mm upward.
http://www.tlc-direct.co.uk/Main_Index/Cable_Index/Armoured_SWA/index.html