Boris Johnson's former ethics chief has said he quit after being asked to advise on a "deliberate and purposeful breach" of the ministerial code.
In an explosive resignation letter, Lord Geidt accused the Prime Minister of putting him in an "impossible and odious" position and added: "I can have no part in this".
Mr Johnson revealed that the row centred on defying trade rules to protect a crucial British industry, and he claimed he was acting within the code by seeking advice.
