Boris Johnson has rejected comparisons from Conservative and Labour MPs between Donald Trump and the Nazis, saying it "demeans the horror of the 1930s".
Dennis Skinner (Bolsover) said Mr Trump was a fascist like Hitler, while fellow Labour veteran Mike Gapes (Ilford South) branded the Prime Minister "Theresa the appeaser" given the speed at which Mr Trump has been invited for a state visit.
Tory MP Ben Howlett (Bath) also cited the Second World War, highlighting a 1940 speech by Winston Churchill and a "dangerous trend towards nationalism, which we've not seen since the 1930s".
However, the Foreign Secretary rejected the comparisons.
Responding to Mr Howlett, he said: "I completely agree that we must stand up against bigotry and nationalism.
"But I must say that I do draw the line, I do draw the line, at the comparison that's been made relentlessly this afternoon between the elected government of our closest, most important ally, a great democracy, and the tyrannies, the anti-democratic, cruel and barbaric tyrannies of the 1930s.
"I think continuing to use the language of appeasement demeans the horror of the 1930s and trivialises our conversation."
The comments came during an urgent statement in the Commons, where Mr Johnson faced pressure to stand up to the new US president after his controversial travel ban on refugees and citizens from several mainly Muslim countries.
Mr Howlett said: "Is the Foreign Secretary aware of the speech in 1940 by Winston Churchill, where he said each one hopes that if he feeds the crocodile enough, the crocodile will eat him last, in reference to those countries that remained neutral in the war?
"This dangerous trend towards nationalism, which we've not seen since the 1930s, inflicting itself upon the western world has wrongly been defined as populism.
"It's clear that this executive order needs to be condemned. Does he (Mr Johnson) agree with me that this House must make its stand here and now, for the weight of history stands on our shoulders?"
Bolsover MP Mr Skinner added: "Will the Foreign Secretary just for a moment try to recall, along with me, as I hid underneath the stairs when two fascist dictators, Mussolini and Hitler, were raining bombs on towns and cities in Britain?
"Now this Government are hand-in-hand with another fascist - Trump.
"And what I say to him - do the decent thing and ban the visit. This man is not fit to walk in the footsteps of Nelson Mandela."
Mr Johnson dismissed the Hitler comparison and insisted it is in Britain's interests to work with the new president.
He said: "I hesitate to say it, but your memory must be at fault if you think Mussolini rained bombs on this country.
"But I hear the comparison that he makes, I don't accept that comparison.
"I believe it's in our interests to work with our American friends and partners to show our disquiet where that is appropriate and to get the best deal for UK nationals and dual nationals."
Labour MP Mike Gapes (Ilford South) went on to call Theresa May "Theresa the appeaser", given Mr Trump was having a state visit far quicker than his predecessors.
Mr Gapes said: "Can the Foreign Secretary confirm that George W Bush was president for more than two years before he made a state visit, that Barack Obama was president for more than two years, and that many previous presidents didn't have state visits at all, although they did visit this country in their duties?
"Why on earth has Theresa the appeaser got him here within a few months?"
The "appeaser" label prompted angry scenes from outraged Conservative MPs, though Commons Speaker John Bercow said the matter "is one of taste, rather than of order".
Mr Johnson said: "I do find it distasteful, distasteful, to make comparisons between the elected leader of a great democracy, the elected leader of a great democracy, and 1930s tyrants.
"I really have to say I think it is, I think it is inappropriate."