Marianne de Trey (1913 - 2016).
Hugely influential potter awarded the CBE in 2006 (aged 93 yrs) primarily worked at Shinners Bridge pottery, Dartington, Devon.
The mark however on this jug (shell / scallop) as photographed was used in 1945-1946 whilst she worked at Sudbury, Suffolk.
Thus the date of production can be ascertained from the mark.
The jug has a chip underneath the spout but no cracks or repairs.
I have researched the price and reduced it accordingly.