Walking across one of the many bridges across the Thames River to get back to the north bank from whence we could catch the Tube back to our hotel, we passed several cast iron panels with these arms painted upon them:
The are, of course, the Royal Arms as borne by Queen Victoria (Quarterly: 1 and 4, Gules three lions passant gardant in pale or (England); 2, Or a lion rampant within a double tressure flory counter-flory gules (Scotland); and 3, Azure a harp or stringed argent (Ireland), and the arms of her consort, Prince Albert of Saxe-Coburg and Gotha.
On his marriage to Queen Victoria in 1840, Prince Albert was granted his own personal coat of arms, which was the royal coat of arms of the United Kingdom differenced with a three-point label bearing a red cross in the center, quartered with the arms of Saxony. The blazon is written as: Quarterly, 1 and 4, the Royal Arms with overall a label of three points argent charged on the center with a cross gules; 2 and 3, Barry of ten or and sable a crown of rue in bend vert.
The Prince's unusual coat of arms was a "singular example of quartering differenced arms, [which] is not in accordance with the rules of Heraldry, and is in itself an heraldic contradiction." (Boutell, Charles, Heraldry, Ancient and Modern: Including Boutell's Heraldry) Prior to his marriage to Victoria, Albert used the arms of his father undifferenced, following German practice.
Why the Royal Arms of the United Kingdom (suitably differenced) in the first and fourth quarters, rather than his paternal arms as would normally be expected there? Victoria and Albert were first cousins, plus the arms of a kingdom normally supersede those of a duchy. Besides, it is apparently what Victoria wanted, and as we all know from Mel Brooks' movie The History of the World, Part I, "It's good to be the king." (Because people give you what you want.)