20 Pounds - Victoria Union Bank of Australia

The Union Bank of Australia was a British-registered colonial bank incorporated under an 1837 Act of Parliament, with its notes circulating across the Australian colonies long before any local central authority existed to regulate them. High-denomination issues like this £20 were instruments of intercolonial commerce and pastoral trade — squatters settling accounts with wool brokers, not everyday currency. The date range 1852–1860 places this squarely in the gold rush period, when the colonial money supply was under severe pressure and private bank paper carried much of the burden.

Perkins, Bacon & Petch were among the most technically advanced security printers of the mid-nineteenth century, their siderographic steel-engraving process making plate duplication and note forgery substantially harder than with earlier copper methods.