Original words and music 1911 by Chas. Collins, E.A. Terry & Fred Terry, as sung originally by Harry Champion with this Youtube recording circa WW2

Meaning of words, in Cockney slang, Darby-kel: Kelly - Belly.
Darby Kelly was a popular song back in the 1800s.
Any old Iron: the call of scrap metal collectors, also another bit of Cockney slang, Iron - Iron Hoof - Poof (Puff) yep, can't use that term much these days :-)

1. Oh, just a couple of weeks ago my poor old Uncle Bill,
Went and kicked the bucket and he left me in his will.
The other night I popped around to see my Auntie Jane.
Auntie said, "Your Uncle left to you his watch and chain."
I put it on right across my vest.
Thought I looked a dandy as it dangled on my chest.
Just to flash it off a bit, I walked around about.
A lot of kiddies followed me and all began to shoutó
CHORUS: "Any old iron? Any old iron?
Any, any, any old iron?
You look neat. Talk about a treat!
You look a dapper from your napper to your feet.
Dressed in style, with a brand-new tile,
And your father's old green tie on.
I wouldn't give you tuppence for your old watch chain.
Old iron, old iron."
2. I shan't forget when I got married to Selena Brown.
The way the people laughed at me, it made me feel a clown.
I began to wonder when the dial began to crack,
If by mistake I'd got my Sunday trousers front to back.
I put the chain on my Darby-kel,
The sun was shining on it; it made me look a swell.
The organ started playing, the bells began to ring,
My chain began to rattle, and the choir began to singó CHORUS.
Now, ladies and gentlemen:
I love the place where I was born. That's good old Bethnal Green
I'm what you call a Britisher. I love my king and queen.
But now we've got some trouble on with Jerry once again
Let us do just what we are told to uphold England's name
We've got the men, the pluck and the courage, too
I'm speaking on behalf of every mother's son of you
Give old England all you can. Be generous and kind,
And before you go to bed tonight, just see if you can findó
Any old iron? Any old iron?
Any, any, any old iron?
An old iron pot, an old iron cot,
An old iron bicycle or anything you've got,
An old iron plate, an old iron grate,
Your mother used to fry on,
And I'm going to let my country have my old watch chain.
Old iron, old iron! 

** End of lyrics