A top economist at the International Monetary Fund (IMF) has poured scorn on what he said is the Fund’s tainted leadership and said he is ashamed to have worked there.

Peter Doyle said in a letter to the IMF executive board that he wanted to explain his resignation after 20 years.

He writes of incompetence, failings and disastrous appointments for the IMF's managing director, stretching back 10 years.

No one from the Washington-based IMF was immediately available for comment.

Doyle is a former adviser to the IMF's European Department, which is running the bailout programmes for Greece, Portugal and Ireland.