British Ambassador Kim Darroch has resigned as the fall-out from his leaked memos continues to roil the relationship between the U.S. and England. In the leaked memos, Darroch referred to President Trump as “clumsy and inept.” The president, in response, promised to shun Darroch, disinviting the British Ambassador from a White House dinner, while calling him “very stupid.”

The details of Darroch’s resignation letter were posted on the U.K. government’s website early Wednesday morning. Addressed to Sir Simon McDonald, permanent under-secretary at the Foreign and Commonwealth Office, Darroch explains:

Since the leak of official documents from this Embassy there has been a great deal of speculation surrounding my position and the duration of my remaining term as ambassador. I want to put an end to that speculation. The current situation is making it impossible for me to carry out my role as I would like. Although my posting is not due to end until the end of this year, I believe in the current circumstances the responsible course is to allow the appointment of a new ambassador. I am grateful to all those in the UK and the US, who have offered their support during this difficult few days. This has brought home to me the depth of friendship and close ties between our two countries. I have been deeply touched. I am also grateful to all those with whom I have worked over the last four decades, particularly my team here in the US. The professionalism and integrity of the British civil service is the envy of the world. I will leave it full of confidence that its values remain in safe hands.

In accepting Darroch’s resignation, Simon McDonald commended the Ambassador for his professionalism over the last few days. Defending him, McDonald wrote, “you were the target of a malicious leak; you were simply doing your job.”

Regardless of whether you view Darroch favorably or not, it was apparent that he would be no longer effective as the British Ambassador to the United States. The two allies depend on the ability to communicate with each other and, more importantly, trust each other. Darroch’s insult of President Trump undermined the bonds of friendship between the two countries.