This is the Lady Patricia, issued around 1930 as the distaff addition to the Patrician, which it resembles in the materials used but in no other way, really, except for the lever box. It’s a simple and elegant design in its own right, shown off by some of the best celluloid Waterman ever employed.
This one is in the onyx pattern. As usual with this pattern, there’s some discolouring, though in this case it isn’t too bad and the original pattern remains clearly discernible. The worst colour shift is in the cap, exactly over the inner cap. Whether this is a result of the decay of the inner cap, the inner cap trapping decomposition gases from the sac or even some pernicious old ink trapped below the inner cap is anyone’s guess.
Though short, these pens are not slender and they make practical everyday writers. Most Lady Patricias I’ve had were stiff-nibbed, but this one has notable flex.