Margery Allingham 
Mr. Campion: Criminologist [EPUB ebook] 

Mr Campion, piloting his companion through the crowded courtyard at Burlington House, became aware of the old lady in the Daimler partly because her chauffeur almost ran over him and partly because she gave him a stare of such vigorous and personal disapproval that he felt she must either know him very well indeed or have mistaken him for someone else entirely.
Juliet Fysher-Sprigge, who was leaning on his arm with all the weariness of a two-hour trek round the academy’s Summer Exhibition, enlightened him.