Boris Johnson has told MPs not to compare Donald Trump to a fascist, as he said people would be "pleasantly surprised" by the new US administration.
Speaking in the Commons today, Labour MP John Cryer asked Johnson: "Isn't it a bitter tragedy that the US, which has been a beacon of democracy and tolerance for so long, has produced a president whose comments and sentiments echo those of the blackshirts 80 years ago?"
Johnson told said it was wrong to make Nazi accusations. "I believe such a analogies and such comparisons trivialise that epoch and trivialise the tragedies of the 1930s," he said.
The foreign secretary has himself got into trouble in the recent past for making Nazi comparisons when talking about the European Union.
During the referendum campaign, Johnson said the EU was an attempt to dominate Europe just as Hitler and Napoleon had.
And in January, he compared French President Francois Hollande to a World War Two guard who wanted to administer "punishment beatings".
Johnson was taking questions in parliament having returned from a visit to the US to meet American officials.
He insisted the special relationship had not been damaged by the "absurd" White House claims that the UK spied on Trump.
"The damage done by such remarks I think can be likened to that of a gnat against a rhinoceros, or an elephant," he said.
"It's not something that will make any difference our fundamental relationship is a great international importance. As for the assertion that there was some sort of collusion by GCHQ to bug the presidential candidate I think that has been accurately described as absurd and ridiculous."
Johnson also told MPs he believed President Trump would act in a different way than candidate Trump.
"The US is moving from a position that we saw during the campaign where we heard some remarks that came across as being perhaps out of line with UK government thinking into position that is much more aligned with our thinking - even on climate change," he said.
But Thornberry said Johnson should be "prepared to stand up and challenge" Trump. "If the secretary of state claims to have influence, he needs to start showing some evidence of it," she said.
She added it would be "unfair" to imply Johnson's influence in Washington was like a "gnat against a rhino" and would "obviously never suggest such a thing".
GCHQ had dismissed claims, first made by a Fox News contributor and later repeated by White House press secretary Sean Spicer, that it spied on Trump as "utterly ridiculous".