Like Rob above, I also used to sing this song on Scout camping trips, usually around the camp fire, now about 25 years ago.

The only verses I remember are these which are kind of covered above but I thought I'd add them as they have slightly different wording:

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I went a-walking with my brother, Jim
Somebody threw a tomato at him
Now, tomatoes are soft and they don't break the skin
But this blighter did, it was still in the tin

To market, to market to buy me a cow
To milk it, to milk it, I did not know how
I pulled on the tail instead of the tit
And instead of milk, I was covered in sh...
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I also remember singing the verse a couple of people list above about someone going out with their coat on backwards, getting hit by a bus and would have survived were it not for having their head turned round. There were other verses that we sang but I don't remember them at all, even seeing all the variations above.

It's a very silly song but I have really fond memories of singing it... :-)