"It's a personal view and there will be many people in this building who don't agree with that view and indeed I don't agree with some of the views that we saw in those letters.

"I think the US administration is highly effective and we have the warmest of relationships and a partnership based on standing up for shared values.

"So I think it's very important that our ambassadors and high commissioners around the world continue to feel that they are able to express those frank views because we have one of the best diplomatic networks in the world and the foundation of that is the free exchange of information and opinions and the understanding that we're not always going to agree with each other but we want to know what people around the world are thinking."