I don’t know exactly what the markings are, I can only make out a V, a lion and an anchor. Any idea on the era and worth? Blue glass Inside
To answer the question in your title: yes, it is a mustard pot. These would often have had a glass liner; I think I see one in your picture but I can’t be sure.
I can see that the mustard and the spoon are by different makers, so are maybe not a matching set. Your pictures are not very clear when the marks are expanded to a readable size but I think that the maker of the mustard may be Horace Woodward & Co:
This means that the “V” is actually “v” and is the date code for 1920/21.
The maker of the spoon, THH, is T H Hazlewood & Co, but I cannot make out the date letter.
Similar plain mustards with spoon and liner are selling on Ebay for 30-50 GBP.
Phil
There’s an “s” on the bottom of pot and a blue glass inside