Flavored black tea. If I had to guess the base might be some unsmoked souchong blend, it is so well blended all the distinctive characters of the black teas are gone. The smell is very peachy but the taste isn’t fruity at all.
The tea is rather expensive in the US, if you’re buying this from the UK then the price isn’t that bad.
sold for $14.40/ 125g in the UK
https://www.fortnumandmason.com/black-tea-with-peach-loose-leaf-caddy-125g
sold for $34.95/ 125g at Williams Sonoma
https://www.williams-sonoma.com/products/fortnum-and-mason-black-tea-with-peach-loose-leaf-tin