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.