Identifying A Crusty Coin

Welcome! Very challenging, and very interesting!
First, let's turn the reverse of your coin right side up...


...and we can see what it was meant to look like, a South African "Kruger pond," or one-pound coin, of 1896:

These were 22 mm in diameter. Yours has lost a millimeter or so to corrosion, but that's the problem: Kruger ponds are gold coins, and would not corrode. What we have here is a brass imitation of a Kruger pond, made at the same time as the original or not long after:
http://en.numista.com/catalogue/pieces13528.html
You may yet be able to make out the tell tale sign of these tokens in the ribbon legend at the base of the reverse, where the Afrikaans motto has been replaced by an English confession of the truth:

Wow - I am stunned ! I honestly thought it would be unrecognisable junk. It's still probably Junk but still mostly unrecognisable. I am so impressed with your knowledge Phil. I can now put the coin in it's place in my collection of metal detecting finds.

Thank you so much.

Jim