Jeff Sims Antiques has dated this piece to the Edwardian era.
The whistle is made by the great Sampson Morden and is hallmarked to both body and attaching ring. A good collector's item, still usable today. Dimensions below.

Postage and packing £8.00 UK
£16.00 Worldwide.
Condition :- Good, with no splits or holes. There is one small area of flattening, commensurate with age and use. The whistle works well.
Hallmarks :- Full set to body and sterling lion to ring.
Date :- Chester 1903.
Maker :- Sampson Morden & Co.
Length :- 4 cms.
Width :- 2 cms. (widest point).
Depth :- 0.5 cms.
Jeff Sims Antiques has dated this piece to the Edwardian era.
Specialists in antique silver, glassware and objects of vertu
You can view the stock and full dealer information on the Jeff Sims Antiques Profile Page