[anarazel]

Normally a country can reject a diplomat's entry into the country. Which makes sense, given the extent of diplomatic immunity. Therefore it does make sense that one cannot willy nilly change a person's diplomatic status while in country.

Edit: delete repeated words

[hndamien]

Technically he is in Ecuador.

[maniacalrobot]

Not really, embassy’s are not the sovereign territory of the foreign country, the land still belongs to the host county, so officially he’s still in Britain, but is protected under the Vienna treaty

[hndamien]

This sounds like you know more about the situation than I do. I just assumed it was considered foreign territory for all intents and purposes. (Maybe due to that treaty).