Looks like some postal stationary item, this site may help. https://www.collectgbstamps.co.uk/explore/stationery/ Edit. Probably from a newspaper wrapper.
Here is a link to a complete wrapper with your example. https://philatelic.co.uk/product/ws4-qv-12d-brown-newspaper-wrapper-stamp-lw2-used-stubbs-weekly-gazette-10/
re: What is it and what is it worth?
