Some of the lost episodes occasionally get found in places like New Zealand where the BBC sold copies to local networks years agoYes, that does still happen... but the spools are so large and the equipment to play them so ridiculous that anybody who managed to hold onto an episode has probably got sick of the hulking great thing and dumped it ages ago. ;-)
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
