Is it acceptable to spur off the existing lighting circuit at the most convenient point, or are there rules to follow when deciding where to spur from?
Most of the diagrams that explain how to add a lighting circuit show it coming from the last junction box / ceiling rose in the circuit. I don't know where the end of my lighting circuit is, and sods law would ensure that it's a long way away from where I want it. I don't want to be drilling or notching joists if I can avoid it.
My plan is to cut a permanent live cable close to where the new lights will be and install a junction box at that point to connect the spur. I'm not sure of the exact topology of the wiring in the loft, but I'm hoping it doesn't matter.