Can I thank all who responded to my my question. It was interesting to see how the discussion went.
For the record we decided not to place the cable behind the skirting but channeled up the wall from the socket through the loft and back down the wall on the opposite side.
I have several runs of cables from sockets on a ring main to spur sockets. The cabling is housed in ducting on the outside of the wall. I would like to bury this cabling into the plaster. Can I do so behind the skirting? Do I need to encase the cabling in conduit? Should the conduit be PVC or metal?