Just wondering.......

From an ex-Brit to all the Brits ........ 
........when an aircraft makes that turn from base leg during a circuit of touch-n-go's or even a full stop landing.......why is it termed to be on "finals" -

........when an aircraft makes that turn from base leg during a circuit of touch-n-go's or even a full stop landing.......why is it termed to be on "finals" -