The Shielding of Mrs Forbes comes from Alan Bennett’s recent book of two novellas,  “Smut” and is read by the author.

The snobbish and priggish Mrs. Forbes is appalled that her son Graham is "chucking himself away" by marrying the unprepossessing Betty. What she (apparently) doesn't know is that her son is gay, and by marrying Betty he is not only ensuring his financial future, but also - he thinks - helping himself and his mother keep up appearances.