For example, Miss Shepherd asks Mr Bennett if she could still live in the van when she becomes the prime minister, to which he replies that he believes Downing St is customary.
Well, perhaps she could stay in the van and secretaries and Cabinet ministers could talk to her through the window. I forget Mr Bennett's reply but I think it was noncommittal as well as straight-faced.
For all the humour there's the tragedy of Miss Shepherd's mental illness, guilt and fear over an accident that wasn't her fault and her unfulfilled musical talent.
Despite his initial reluctance, Alan Bennett becomes her friend while she supplies him with a story, an unusual tragic / comedy in which Miss Shepherd and Alan Bennett are the stars.
Congratulations Kerry, cast and crew!