It should be noted that all these pictures relate to each other.
Here is a UK 3 Pin Plug where the cable has not been gripped by the clamp inside the socket. When wiring a plug the core colours should not be seen externally.
Here we are inside the plug and we can see some issues, notably the foil around the fuse which I was informed by the customer was because the fuse kept blowing! Secondly we can see why the cable was not clamped, the clamp is broken. The third issue is that the plug is not wired properly, yes the colours are in the correct place but the conductors should be cut to a suitable length so they are not creased in the plug and this also allows the cable to be clamped properly in place.
And we then come to the reson for the foil around the fuse, a hob with 4 hotplates on it. Bearing in mind a 13A fuse will tolerate 3kW (3000w) of power being drawn, you are looking at a hob that has the potential to draw 4kW of power which relates to a fuse of at least 17A needs to be in the plug. As there is not a 3 Pin plug that meets BS1363 this is not going to happen. This hob in the first instance should have been wired to a suitable outlet and also the hob itself should have been fitted properly so it is not portable.
Take no notice of the cooker it is on, apparantly the rings on that didn't work hence the reason for the separate hob.