Whenever one looks at a photograph of a miniature object, such as a scale model of a train or car, there is almost always some visual clue that gives the game away, no matter how hard the modeller has worked to achieve perfect miniaturisation.

We have recently acquired a miniature carriage clock of such high quality that such normal rules of thumb do not apply. Of English manufacture, the brass castings from which it is assembled are masterpieces of precision engineering, with each angle and corner perfectly sharp.

The piece de resistance is the engraving, however: the sides and back are solid and bear scenes of Westminster Abbey, St Paul’s Cathedral and the Royal Exchange respectively; the plain silvered dial has a less elaborate depiction of Tower Bridge.

There is even decorative engraving on the platform of the escapement, visible through the top glass. Astonishingly it also has what is known as blind silvering as well as gilding, a microscopic technique that is normally only seen on jewellery

There is no signature but a masterpiece of miniaturisation like this can only have been produced by a top London maker