Jenny Runacre as Miss Brunner, mid-scene, basically chewing through the entire cast.
Moorcock famously despised Fuest’s script. Halfway through filming, the cast genuinely couldn’t tell if it was meant to be a comedy, so they finally cornered Fuest to ask. He told them yes, and from that point on everyone started playing for laughs.
Runacre, of course, didn't need the note.
The Final Programme (1973). Still not sure if she's the new messiah or if she just casually outacted the entire ending.