Off One's Box Meaning

(Britain, idiomatic) Stoned or intoxicated.

Example: 1896, Surgical Journal, Volume 2, page 227:
  Say, if you call that acting well, you're off your box.
2008, Gary Flockhart, "These Modfathers aren't all they're cracked up to be", The Scotsman, 24 April 2008:
  "The conditions are disgusting aren't they?," he continued. "I don't know how people can. I mean, you'd have to be off your box to stay there for three days wouldn't you?
2012, Deborah McAndrew, A Government Inspector, Methuen Drama (2012), ISBN 9781408173657, page 83:
  Annie Anthony! Anthony! Don't you know what's happened here? Sir Jonathan has asked for our daughter's hand in marriage.
  Belcher Marry our Mary? Are you off your box, woman?
2007, Dianne Bourne, "Ryder happy to toe smoking line", Manchester Evening News, 11 July 2007:
  The 44-year-old has admitted to cleaning up his act of late, kicking well-publicised drug addictions and now leading a healthier lifestyle with regular exercise and a passion for fruit smoothies.
  He told the M.E.N. last week: "Innit just natural that when you're a kid you're off your box and when you're a grown up, you're not? It seems totally normal to me, that."
2010, Martina Cole, The Family, Headline (2010), ISBN 9780755375523, unnumbered page:
  'Oh yeah, much happier, darling. I saw her smiling yesterday, a real smile and all. Not one of those weird ones she does, when she's off her box on the pills …'
2012, Mike O'Leary, Misfits, Hodder & Stoughton (2012), ISBN 9781444761771, unnumbered page:
  So you know when you're off your box and you're dancing to this tune and the tune is one of your favourites, yeah? But because you're off your box, it's better than banging.