unknown letter under the hallmark

first of all pls forgive my English.
Here is the question: I saw a little tea pot by Viners of Sheffield, it has on the bottom the corporate mark Alpha plate Viners of Sheffield but under I cannot see “England” as usual, but there is the letter T.
Can someone explain me what does it mean?
Obviously I know the item is silver plated, but I think it may be imported from eastern countries (as Viners sometimes did)!
Thanks a lot for any information you can give me.