Part of his job is to appraise Her Majesty's government of the situation in the country he is sent to. If he does not do this because of fear that the host government will find out and disapprove, he is hamstrung and cannot do his job. Thats why his communications are supposed to be completely confidential. Whoever has leaked these communications from within the foreign office is guilty of treason.

Farage says that he is unsuitable because he is a globalist. What else is an ambassador who has served in several countries supposed to be? You cannot just have an ambassador who is a sympathiser with the current regime in the country to which he/she is sent. Does the ambassador to China need to be a communist? Does the ambassador to Saudi Arabia need to be an Islamist? They should have a working knowledge of the country to which they go.