In my best Scottish accent:
"Errm, hello, yes. Gordon here. Brown. Gordon Brown. Your Prime Minister. Yes of course I run the country. Well yes you could have a point there. I think I'm good at my job..... I'd like to say how nice it was speaking with you"
I'm tempting to write to him asking him to resign and then see if he rings me
BBC NEWS | Politics | Brown telephones voters at home