I'm replacing wiring to a socket that was run on a spur underneath the carpet
(!). I have some skirting trunking that will take care of running it around
the edge of the room, and I'm planning to extend the ring using 2.5mm2 T&E
in the bottom of the trunking.

What are the requirements for cable attachment in this scenario? Ordinarily
I'd assume it would need clipping, but is that the case inside trunking?
It's literally resting on the floor at this point, so there's no need to
support it at all, and it's protected at the front by the face of the
trunking. I will obviously clip it where it emerges from the trunking to
sockets.

I ask because it's a bit tight and so it's going to be awkward to clip
inside the slot it runs in - the slot which also means it's constrained top
and bottom. It isn't anywhere near a route of egress and if the trunking
melted it would fall about a millimetre.

Does being in floor trunking count as sufficient attachment?

Thanks
Theo