Margaret John appeared in two Doctor Who stories: as Megan Jones in Fury from the Deep and Grandma Connolly in Tardisode 7 and The Idiot's Lantern.
John held the record of the longest gap — 38 years — between Doctor Who appearances.[1] (Although there was a 39-year gap between Bernard Cribbins' on-screen appearances in the franchise, he had guest-starred in a Big Finish audio drama before his appearance in 2007.)
Her television career spanned over five decades, from Bronwen in a 1960 BBC production of How Green Was My Valley to Old Nan in the first season of HBO's Game of Thrones, which aired after her death in 2011.