Exhibit Antiques has dated this piece to the Victorian era.
Large polished pontil.
This is a very rare piece and although its not signed it was almost certainly at the "Non-Such Flint Glass Manufactory" in Bristol, owned by Isaac Jacobs.

You can see an example of his gilding at the V&A in London.
Date & Origin
England, c1810-20. Period of Victoria
Condition
Excellent, no chips cracks or restoration.
Dimensions
Height: 9.2cm Rim diameter: 21.5cm
Exhibit Antiques has dated this piece to the Victorian era.
Specialists in 18th & 19th century antique glass
You can view the stock and full dealer information on the Exhibit Antiques Profile Page