I purchased this 'London mug' as a gift for a friend coming to visit from Germany who loves to visit London and adores our royal family it was, I thought suited for her. She was thrilled to receive it and now takes pride of place on her mum's dresser (who also loved it). a multi use gift, not just for coffee!!.
As the other customer said while the dimensions are on the site I think most people expect it to be a standard size so they don't give much thought to checking the measurements.
However as well as being the size of a child's mug it also feels very flimsy and thin.
But I do love the design and will be keeping it! I don't regret my purchase but I won't be drinking from it as I think it could easily break if another cup came in contact with it while washing up or something.
The illustration on this mug is wonderful, but the mug itself is very small.... that said, the dimensions on the website are correct and I guess calling it a "coffee" mug is a hint, but I think it's worth pointing out that this isn't a standard mug size. Also the picture suggests there's an illustration inside the mug as well as on the outside - but there isn't! Still an unusual item, though.