1Amp 240V Cartridge Fuses from here

[ppppenguin]

I agree with Trevor that there's plenty of modern kit that's not adequately protected. For a wall wart the only real requirement is that it should stay safe under fault conditions. This could be done with a fuse, a heat sensor in the transformer (if not a switchmode), a PTC and there are probably other methods too.

Eisteinagogo's comment about control wiring reminds me of a clause in the wiring regs about how in certain cases, such as feeds from busbars to lower current circuits, these cables can ultimately be regarded as sacrificial.