(and only Nutter!)
The origin of this slang word is the TV Ad for Dime Bars (now Daim, made by Kraft Foods), a chocolate covered crunchy caramel candy bar, which aired back in 1995.
The Ad featured the British comedian Harry Enfield playing a slobbering retard
in a supermarket, filling a shopping trolley FULL of dime bars... he's approached by a well spoken interviewer (Also Harry Enfield), who asks him 'Do you remember your first Dime?'... anyway, the ad finished with the retard
exclaiming to his wife:
"That bloke's a nutter... OI, NUTTER!"
Google the phrase 'dime - that blokes a nutter' and you'll be sure to find many videos of this wonderful ad
Many of us will also remember the Armadillos from the second ad they did!