"Mog" ran for 13 episodes on ITV in the summers of 1985 and '86. Based on a novel by Peter Tinniswood, "Mog" was inevitably compared with the much funnier sitcom "Porridge": both comedies were written by the comedy team of Clement & La Frenais, and both comedies featured an incarcerated criminal as the main character. But all similarities ended there.
Mog is a career criminal (a cat burglar, hence his nickname) who won't give up his trade, but who isn't good enough at it to survive on the outside. To avoid prison, he fakes insanity and gets himself committed to the Briardene mental hospital. The security at Briardene is less stringent than it would be in Her Majesty's Prisons, so Mog has no difficulty popping out of the insane asylum at night in order to pull off his burglary jobs, then sneaking back into the asylum (his absence undetected) along with his swag.
I really, really, really dislike movies and tv shows that sentimentalise mental illness or depict it dishonestly. None of the inmates in Briardene have any discernible mental affliction. All of them are eccentrics or dreamers who simply can't 'cope' in the real world, so they have chosen to withdraw into the peace and comfort of a mental asylum. Having actually visited several mental institutions (in Britain and elsewhere), I find this premise quite offensive.
"Mog" was well directed by Nic Phillips, who later proved his versatility on "Barbara". But "Mog" just wasn't very funny.