The Whitney Straight design was so popular, that Miles decided to take advantage of this and improve it even further, whilst maintaining the standard of quality and its general form.
In 1938, they produced an improved model, incorporating all the features which experience with the Whitney Straight had shown to be desirable.
The new model, which was named the Monarch, had an additional seat and was luxuriously finished both internally and externally, embodying such refinements as a fool-proof glide-control and a special one-piece moulded windscreen of increased depth. The wings, which did not fold for stowage, were interchangeable with those of the Magister, which was then in full production.
Numerous Monarchs were built and sold, but Service demands for the Master I trainer prevented production in sufficient numbers to meet the great demand. The Monarch, however, together with the Whitney Straight, gave excellent war service on R.A.F. communication duties, and many of both types were still in operation in 1944.