Here are the lyrics from the Ronnie Barker version, as best as I've been able to hear them.

THE STUTTERING BUM
(from Ronnie Barker)

Mary-Lou, I'm a-calling you up on the telephone
To say thanks for coming to the dance with me and letting me take you home.
I'm sorry I seemed so nervous and started to stammer and sweat,
But it s-started as s-soon as I saw you, and I ain't got over it yet.

I stared at your great big b-b-b-b-b-beautiful blue-green eyes,
I wondered if you f-f-f-f-f-flirted with all the guys.
When you smiled at me, I nearly sh-sh-sh-sh-sh-shot right out the door,
'Cause I'd never seen such pretty little t-t-t-t-t-teeth before.

I ain't usually a bashful boy, I've took out other gals.
I've kissed them on the b-b-b-b-b-back door step and p-p-p-p-promised to be pals,
But since I first caught sight of you on the Brownsville Buggy Ride,
Why, I've become a s-s-stuttering bum and my tongue's perpetually t-tied.

My c-c-c-c-c-c-c-c-c-c-collar gets awful tight,
When I f-f-f-fear(?) it grows as I did last night,
I get a funny feeling in my b-b-b-b-b-b-b-b-b-b-brain,
And I can't ????, just gotta see you again.

She said she'd see me Saturday, and I put down the phone.
My tongue is back to normal now, and I'm off once more alone.
But next time that I meet her, on Saturday night around ten,
You can b-bet your b-bottom dollar I'll be a stuttering bum again.

I'll grab her by the b-b-b-b-b-barn and p-p-push her inside.
I'll take my c-c-c-courage in both hands and ask her to be my b-bride.
And if she holds my c-c-c-clammy hand and tells me that she would,
I'll f-f-f-f-fetch a preacher right away, that'll cure my stutter for good.

That's good! That's g-g-g-g-g-g-g-g-g-g-good!