Gatwick Security - External Battery Pack

Hi all,
Thinking of picking up an external battery charger (the ones that you use to recharge your iPad iPhone on the go). Has anybody tried going through the new security with these? Can you even pack these in hold luggage and is that a better option?
I could probably do without it, but I would like to take one with me considering we are spending 3 weeks in Orlando, so any help greatly appreciated.
Thinking of picking up an external battery charger (the ones that you use to recharge your iPad iPhone on the go). Has anybody tried going through the new security with these? Can you even pack these in hold luggage and is that a better option?
I could probably do without it, but I would like to take one with me considering we are spending 3 weeks in Orlando, so any help greatly appreciated.