A lady called Joan Hunter Dunn was immortalised by which British poet?

Joan Hunter Dunn (1915-2008) was the muse and friend of the British poet John Betjeman (1906-1984), Poet Laureate from 1972 until his death, and also famous for inviting friendly bombs to rain on Slough.

Not everyone realises that the central character of his 1941 poem "A Subaltern's Love-song" was, in fact, a very real person, and a rather remarkable one.

She was highly educated, holding a diploma from King's College London, but it is fair to wonder if Betjeman was primarily thinking of her mind when, despite being married for seven years, he saw her for the first time and composed a poem fantasising about the two of them playing tennis together. Joan, too, was married, to a civil servant and later radio producer called Harold Jackson, and the two of them spent time in Rhodesia (now Zimbabwe) and Singapore.

She and Betjeman kept in touch by correspondence but, sadly, her letters from him were stolen in 1996.