Well seeing as the new Doctor Who series is out, I bought this for my cousin who is a massive Doctor Who fan (as am I).
When I read the intructions it told me that there were two exterior 'Activation buttons' that would make the end light up, one on the side and one hidden under a cap at the bottom. I tried both and they seemed to work fine. There is also a switch which extends the end, what they call the 'Emitter'. However, when the end is extended, the button on the side doesn't work.
When I detached the bottom on the screwdriver (which lets you get to the battery case) I discovered the problem. When the end extends, the whole interior, including the battery case, shifts up. This means that the pad/button on the battery case that was being pressed to activate the light before was now in the wrong place. To correct this, the designer had put in a second button lower down so that when the end extends the exterior button will still work by pushing the second button. But the second button itself is too low, so when the screwdriver extends it can never work. This is actually a design flaw by the manufacturer and not a faulty product, so will appear on EVERY one they produce, unless they correct the problem.
Such an obvious flaw which causes the toy not to work in this way is really not acceptable, especially considering that most children will use the button when the screwdriver is extended, as the Doctor does.
£16 for this toy would be a reasonable price considering how much its predecessors costed when first released and considering it's popularity when linked with the show, however with a problem like this it feels like a rip off and as if I've bought some dodgy version of the toy, rather than the way it's advertised on a website like Amazon, which I trust.
Avoid this at all costs, it's a complete waste of money and you are better off waiting for an official version of the screwdriver to come out.