If you are sure that behind the skirting is the best place*, then one of the problems that you are trying to avoid, is that someone will hammer a nail or drill a hole through the skirting and penetrate the cable. This might not be particularly likely, but it is very difficult to put such a strong steel armour round the wire that it is impossible, the usual method is to use an earthed steel conduit so that although a person can still nail through it, the nail will be in contact with the earthed conduit and cause the protective fuse to blow.
In that case, one way is to take off the skirting (this will usually cause some damage to the plaster or the skirting which will mean you have to do some redecorating.
You will usually find that in an old house the skirting is fastened to bits of wood nailed or bricked into the wall, and there is a small irregular gap behind the skirting. In a modern house the boards may be nailed or glued direct to the wall. Instead, it is possible to run a timber batten (say 18mm square) against the wall, up against the bottom of the plaster, and another just above the floorboards.
This gives you a channel between the battens where you can run your cables in their conduit; and you can screw or nail the skirting to the battens.
This is a method I have used for TV aerial and hifi speaker cables, which can be a bit of an eyesore, I don't do power cables this way but it is a possible approach.
When redecorating, you can repair the plaster so that it meets the battens which you have aligned to the top of the skirting, before you put the skirting back.
*It is usually preferable to run the cables under the floor. It is also possible to chase the cables into the plaster, running it horizontally between socket outlets. This is very handy on a ring circuit where you may have a lot of sockets in the room, not very far apart.