FACTBOX-Britain's political and diplomatic class angry at U.S. envoy's exit

LONDON, July 10 (Reuters) - The resignation of Britain's ambassador to Washington following stinging criticism from U.S. President Donald Trump has infuriated London's diplomatic and political class.

Kim Darroch quit on Wednesday after his leaked memos describing the U.S. leader as inept prompted a withering Twitter attack by Trump on both him and outgoing British Prime Minister Theresa May.

Senior figures in May's government and the opposition Labour Party accused Boris Johnson, favourite to be next prime minister, of contributing to the resignation by failing to back Darroch. Below are reactions:

BRITISH PRIME MINISTER MAY:

"I have spoken to Sir Kim Darroch, I have told him it is a matter of great regret that he has felt it necessary to leave his position as ambassador to Washington," May told the House of Commons as lawmakers shouted "shame" and "disgrace".

"Good government depends on public servants being able to give full and frank advice ... I hope the House will reflect on the importance of defending our values and principles, particularly when they are under pressure."

FOREIGN MINISTER AND PM CANDIDATE JEREMY HUNT:

"I am outraged that a selection of his reports should have been leaked."

"I profoundly regret how this episode has led Sir Kim to decide to resign. He deserves to look back upon his career as a servant of Britain with the greatest satisfaction and pride."

JUNIOR FOREIGN OFFICE MINISTER AND CONSERVATIVE LAWMAKER ALAN DUNCAN:

"He (Boris Johnson) has basically thrown this fantastic diplomat under the bus to serve his own personal interests."

"His sort of disregard for Sir Kim Darroch and his refusal to back him was, in my view, pretty contemptible but also not in the interests of the country he is trying to lead."

TRADE MINISTER LIAM FOX:

"I was with Sir Kim last night in Washington. In a very difficult period, he was showing his customary professionalism."

"Somebody has, for whatever malicious reasons, sought to either damage the UK-US relationship or indeed Sir Kim personally. I don’t know what the motivations would be at this stage but it is very important that we find out who actually carried out this particularly damaging act."

"It is important that our ambassadors are able to write frankly to politicians. If they have to do so worrying about how it might look in a newspaper it will represent a fundamental change in how our diplomatic system operates."

OPPOSITION LABOUR LEADER JEREMY CORBYN:

"Boris Johnson's refusal to support Kim Darroch shows he won't stand up to Donald Trump, or stand up for Britain. Johnson wants a sweetheart trade deal with Trump that would open our National Health Service to U.S. corporate takeover. I'll never let another country's leader choose who represents the UK."

HEAD OF BRITAIN'S DIPLOMATIC SERVICE SIMON MCDONALD:

"The leaker is guilty of the worst breach of trust in our service in my career. The damage after three days is evident in the resignation of the most senior British diplomat."

"The last time I know that we had difficulty with the United States was 1856 when the incumbent was accused of recruiting Americans to fight on the British side in the Crimean War when Franklin Pierce was in the White House."

FORMER UK AMBASSADOR TO WASHINGTON CHRISTOPHER MEYER:

"I am extremely angry that a good man has been brought down by a terrible leak of highly classified documents and by a president as vindictive and spiteful as Kim Darroch said he was in his highly classified communications."

FORMER TOP CIVIL SERVANT AT THE FOREIGN OFFICE SIMON FRASER:

"It's a very serious situation because the consequences for the relationship with the United States, which were already difficult under the current president, are clearly very significant. This is the last thing you want in the relationship between two very close allies." (Reporting by Kate Holton, Costas Pitas and William Schomberg; Editing by Andrew Cawthorne)