The flag of South Georgia and the South Sandwich Islands features a blue British ensign with a coat of arms in the fly. The aspect ratio is 1:2. The blue color code is #00247D.

In detail:

1. Blue Ensign: The flag has a blue field, occupying the entire background.
2. Union Jack: In the upper hoist-side corner (canton), there's a Union Jack, which measures one-quarter of the flag's length and half of its width.
3. Coat of Arms: Positioned in the fly, it takes up approximately half of the flag's length and one-third of its width.

Note that the description provided does not include the symbolism of the flag or the specific details of the coat of arms, as requested.