During a 1982 show of the "Hot Space" tour during "Brighton rock" Brian had a string break on his Red Special so he tossed that one to his tech who caught it and took the Birch which was his back up.How’d it get broken, can’t imagine it was done deliberately?
But then got frustrated with the Birch and tossed it to his tech but the tech wasn't paying attention, at which the Birch hit the floor and broke its neck and headstock off.
So Brian used his Flying V, as his third back up to finish the show while his Red Special needed a new string and his Birch was DOA.
Here's that actual performance where it all went devastatingly wrong for the Birch. 3:30 ish the RS suffers snapped string. 3:47 the Birch makes an appearance and sounds bad! 5:08 for about 15 seconds the Birch goes bye bye. The next guitar you hear is the Flying V.