Lyric discussion by casper2095 

Cover art for Mummy Can't Drive lyrics by Angelfish

I suspect there's an awful lot more in these lyrics than a bit of drink driving...

"There's too much inside" - is a bit of a pathetic line if we're just talking about too much booze. I'll propose she's talking about too much emotion inside.

The tussle with mummy, grandpa, and grandma all crying out "Come with me darling" makes me think that the song is about a child custody dispute. Mummy is in a trauma and wants her "darling" (a "little boy"?) because "we've got to get out to survive". Note that mummy has a "pistol on the side", presumably to enforce her will over grandma and grandpa's.

"Mummy can't drive" is perhaps an acknowledgment from mummy that despite knowing her destructive influence on the child, she cannot suppress her maternal instinct to be with him. And hence the song is tragic, distressing, and potentially violent.

My Interpretation