In 1953 Barnett arrived on BBC television as one of the panel of
''What's My Line?'', which made her a household name. She appeared on the programme for ten years but was not an original panelist, her seat having been previously occupied by
Marghanita Laski. She was regarded by audiences as elegant and witty, the epitome of the British
aristocracy, although her title actually came from the fact that her
solicitor husband had been knighted; the form
Lady Barnett suggested she possessed a
courtesy title, but she was not an aristocrat, nor had she married into the aristocracy. She also made regular appearances on the BBC radio series
Any Questions, on the radio panel game
Many a Slip and on the women's discussion series
Petticoat Line. She was greatly in demand as an
after-dinner speaker, a role into which she slipped confidently. In 1956, a reviewer predicted that an alien visiting from another planet could ask anyone between the ages of seven and 70 "What is ''What's my Line?
" and "Who is Isobel Barnett?" and be confident of getting an answer. She featured in the first revival of What's My Line?'' which ran for two series from 1973 to 1974. ==Later life and death==