“The Boys of the Old Brigade” is an Irish republican folk song by Paddy McGuigan. It was sung by Irish Republican Army member Maguire to Thomas Shelby at The Garrison Pub, in Episode 1.3. The lyrics are as follows:
“Oh, father, why are you so sad
On this bright Easter morn'
When Irishmen are proud and glad
Of the land Where they were born?
Oh, son, I see sad mem'ries view
Of far-off distant days
When being just a boy like you
I joined the IRA.
Where are the lads who stood with me
When history was made?
A ghrá mo chroí, I long to see
The boys of the old brigade."
The song was written in 1966.