Mum specifically warned Dad (Bob) against buying pearls for her 21st. It was the 1970s. Being a talented dressmaker she could make her own fashionable clothes and pearls, well, they didn’t excite a modern young woman. The Housemans were far more traditional in their taste and more general approach to life. Early intervention was warranted.
When Bob handed her a smart red leather case her thoughts would have run first to silver, possibly even to gold. Until she lifted the lid. I feel certain that there was a necessary re-arrangement of her face as she hoped to look grateful for something she specifically did not want. Bob on the other hand would have been struggling to disguise a smirk as would his sister, Christine.
I wonder how long he made Mum struggle before revealing that these pearls belonged to his sister, her own 21st birthday present, and from which she had only willing parted from for the duration of the joke? It was worth it. The joke has lasted for fifty years. I don’t actually know what the real present was!
