I know the name sounds a bit "Davey-wavey-gravy" but I have just tried this company's "Classic Cinnamon spice" tea.
It has cinnamon cassia, cardamom, ginger, cloves black pepper, cinnamon extract and ginger extract as its ingredients.
Boy! Is it pungent! My cupboard now smells exclusively of cinnamon.
It tastes nice as well.
http://www.goldentemple.nl/yogitea_gb/ExoticTeas/Classic.htm l
DOH!
Tesco. You can also buy from those here:
http://www.goldentemple.nl/yogitea_gb/WhereToBuy/WhereToBuy. html