danny la rouge
More like *fanny* la rouge!
They're wrong. Really.So if he can and has resigned he is no longer PM, which is what I said they are reporting
What happens is that the incumbent concedes defeat. Then the leader of the party that can form a government goes to the Queen. She asks him if he can form a government. He says yes. She appoints him PM. Until she does that, the previous incumbent is still PM.
If, on the other hand, Brown resigns, then his deputy becomes acting PM, before going to the Queen to be appointed PM as swiftly as possible.
If Brown does that, that would be pretty stupid, given that that person will then need to concede to Cameron, and go through step one above.