Bathrooms in the UK may have a shaver socket that is (to my understanding) limited to supplying 200mA, is protected by an isolation transformer and uses a two pronged plug similiar but not identical to the common Europlug (BS4573).
I just bought a shaver that came with a BS1363 plug, the common 3 rectangular pronged plug in the UK. Is it safe and allowed to adapt between the two? According to wikipedia, BS1363-3 allows adapting a BS1363 socket to a BS4573 plug. That is, it allows plugging in a shaver with a shaver plug into a regular BS1363 socket. It does not seem to allow going the other way.
I think this is safe to do, the load I want to use consumes on the order of 50-80mA and is doubly insulated (it is a shaver after all). The only concern one might have is that such an adapter might allow a person to plug in a more problematic load. Then again, the shaver socket already has provisions for plugging in an american two pronged plug.