The lyrics I learned were:

In a bombed-out garret, so lowly and so mean,
Oh, smell the pungent odor of nitroglycerine.
Three busy little children are filling cans with nails.
They're busy building fuses as they sing this mournful wail.

Freedom, freedom, we'll live to see the day,
Freedom, freedom, a child shall lead the way.

Let's draw lots to see whose turn it is to throw the bomb.
Johnny's hand is trembling, he's trying to be calm.
Polly's face is ghostly white, she's gripping Johnny's arm.
The third to wait for freedom's sake is little brother Tom.

(Chorus)

Johnny smiles, so proud is he, for he has won the right.
His little hands picked up the bomb and stole into the night.
Tom and Polly waited till the dawn had turned to day,
And the two brave little children sang out this mournful way (lay?)

(Chorus)

Let's do the job together, it's our turn to throw the bomb,
Let's hope our aim is better than unlucky brother John.
They followed in his footsteps, now forever they are gone,
But in some bombed-out garret, freedom's children carry on.

(Chorus)