What was the last valve ?

[beam me up schottky]

Just to clarify, I meant the last valve to be actually designed and introduced to the market, excluding old valve types being currently manufactured.
Suppose I should say excluding specialist types that may have been designed since.
At some point, Mullard, Mazda etc must have decided to end valve design and production as an obsolete technology, thats really what I'm saying.
Have to say I'm also inclined to think it must have been a TV type.