Chas & Dave: Gertcha

Now there's a word that I don't understand
I hear it every day from my old man
It may be Cockney rhyming slang
It ain't in no school book
He says it every time that he gets mad
A regular caution is my old dad
Rub the old man up the wrong way, bet your life you'll hear him say
Gertcha, cowson, gertcha
Gertcha!
When the kids are swinging on the gate
Gertcha!
When the paperboy's half an hour late
Gertcha!
When the pigeons are pecking at his seed
Gertcha!
When the farmer (?) starts digging up his weeds (?)
Gertcha!
Gertcha, cowson, gertcha
Bar stool preaching
That's the old man's game!
Now the old man was a Desert Rat
Khaki shorts and a khaki hat
How me mother could have fancied that
I just don't know
But when the enemy came in sight
They gave up without a fight
They rubbed him up the wrong way
This is what they heard him say
Gertcha, cowson, gertcha
Gertcha!
When me rock and roll records wake him up
Gertcha!
When the Poles knock England out of the cup
Gertcha!
When the kids are banging on his door
Gertcha!
When the barman won't serve him any more
Gertcha, cowson, gertcha
Bar stool preaching
He's always been the same!
(piano solo)
Gertcha, cowson, gertcha
Gertcha!
When the dog's left a message on the step
Gertcha!
Lester Piggott, when he lost it by a neck
Gertcha!
When me brother kicks the toes out of his shoes
Gertcha!
When the houseflies are flying round his food
Gertcha, cowson, gertcha
Bar stool preaching
He's always been the same!
Gertcha!
Gertcha!
Gertcha!
Gertcha!
Gertcha!
When me mother says he can't go down the pub
Gertcha!
Sister's boyfriend put his sister up the club
Gertcha!
When the tomcats, when they're kicking up a din
Gertcha!
Tottenham Hotspur couldn't get one in
Gertcha!
When me mother locks him out of the flat
Gertcha!
When it's raining and he can't find his hat
Gertcha!
In the mornings when his motorcar won't go
Gertcha!
Next-door neighbour, when he won't give him a tow
Gertcha!
Gertcha!
Gertcha!
Gertcha!