Throw the dolly out of the pram

What does the phrase "threw their dolly of the pram" reference and what does it mean exactly? Here is the sentence in which I found this phrase:

It is hardly surprising, then, that when someone came along and challenged the version of history on which their new-found importance in society was to be based, they threw their dolly out of the pram, as the prison wardens in the prison in which I worked used to put it to describe the actions of a prisoner who had lost his temper.

In my experience "threw their toys out of the pram" is more common. It means they responded to frustration with an irrational and seemingly dispropotionate outburst; like a baby repeatedly throwing away everything it can get its hands on. A less common variation is "spat out their dummy"

Sorry for the spelling error Ahmad Ragab - dispropotionate should, of course, be disproportionate. I'm sure you will have guessed that but I had to come back because ESC's answer reminds me you might be more at home with US English and not understand the word 'dummy', which is a rubber teat that a baby is given to suck on. I think it's called a 'comforter' in the US.