On 31 May 1910 these four colonies came together to form the Union of South Africa and the individual colonial flags were no longer used and new South African flags came into being. Once again, as a British dominion the British Union Flag was to continue as the national flag and the standard British ensign pattern was used as a basis for distinctive South African flags.
As was the case throughout the British Empire, the Red and Blue Ensigns were the official flags for merchant and government vessels at sea, and the British Admiralty authorised them to be defaced in the fly with the shield from the South African coat of arms. These ensigns were not intended to be used as the Union's national flag, although they were used by some people as such. Although these ensigns were primarily intended for maritime use, they were also flown on land.
The design of the Red Ensign was modified slightly in 1912 when the shield was placed on a white disc so as to make it more distinguishable. The Red Ensign continued to be used as the flag of the South African merchant marine until 1951.
Most mass-produced flags are commonly 150x90cm / 5x3' or 90x60cm / 3x2', which will often vary from the official size ratio. We now offer a custom-manufactured official size option for our many of our flags.