The Kings whistle model by J, Hudson & Co;

                                      
L: 4" / 101.67 mm Top Cap Diameter: 1" / app 25.3 mm
 A Beaufort whistle with mouthpiece, This sample is a Railway, L&NWR,
London and North-Western Railway,  it is one of their Best Made models, Bickel Silver, made  1888 - 1909. 
 Being an expensive model this model was probably made for a station master.
The Company still exists today .
This model still appears in their Acme whistles 1930's catalog, Model #177 other samples of this model have stamps as Shand Mason. Or Hudson's Patent. and have a shorter body  
(Tottal L:97.6 mm) 
See an article here about J Hudson & Co, Acme Whistles, History and links to other artcles here.
Whistle museum , A.Strauss All rights reserved.