I guess my comic book reading is limited because I keep returning to the same stories and creators. Captain UK was a parallel universe version of our own Captain Britain. Linda McQuillan came from Earth 238 where all super-heroes had been wiped out by the lethal creature know as the Fury. This massacre has left her so emotionally scarred that she was unable to use her powers until the events of the Jasper's Warp forced her to re-don her costume. She briefly went on to join a team called Excalibur but I don't think she has been used much since the 1980s. A B-list character but an interesting one.