A Boris Johnson aide has sparked fury after suggesting the UK should have a "special relationship" with Hungary's far-right leader.
Tim Montgomerie, who was the PM's social justice advisor in September, heaped praise on Hungarian leader Viktor Orban.
Labour called for Mr Johnson to "remove him immediately".
A Government spokesman said he had "not currently been returned to his position" following the election.
Orban has been widely condemned for attacking Muslim and Jewish minorities and suppressing free speech and freedom of the press.
And he's been accused of fostering anti-semitism with his “relentless campaign” against the Hungarian-born billionaire George Soros .
Conservative MEPs were the only members of a governing party who voted to oppose a motion in the European Parliament condemning Orban in September 2018.
Orban later sent Tory MEPs a letter thanking them for their "solidarity" in opposing the vote.
And in a speech hosted by a right-wing think tank in Budapest in December, Mr Montgomerie praised Hungary's "early thinking" on the "limits of liberalism."
He told the audience at the Danube Institute: "I think there will be very significant investment by Boris Johnson in relationships, particularly bilaterally, with key European states. I think the French relationship will be significant, and I think this relationship with Budapest will be significant as well.
“Budapest and Hungary have been home, I think, for an awful lot of interesting early thinking on the limits of liberalism, and I think we are seeing that in the UK as well. So I hope there will be a special relationship with Hungary amongst other states.”
He went on to compare Mr Johnson to other "populists" such as Orban, Nigel Farage and Donald Trump .
He said: "Why are people voting for Boris and Viktor and Nigel [Farage] and Donald? Those questions aren’t asked enough.
"And so whatever populism is, it isn’t really about any of the people on the stage, it is about long-term trends in economics and culture that are changing how people align themselves.”
The remarks were not signed off by Downing Street.
A Government spokesman said: "All special advisers are expected to comply with the special adviser code. During the election all special advisers resigned their positions.
"Tim Montgomerie has not currently returned to his position following the election."
Before joining Mr Johnson's team, Mr Montgomerie was a journalist and editor of the Conservative Home website.
He also worked as a speechwriter for then-Tory leaders William Hague and Iain Duncan Smith.
Labour's Jon Trickett said: “These comments from one of Boris Johnson's senior advisers are despicable.
“Cosying up to a government which peddles antisemitic and Islamophobic rhetoric, attacks migrants and refugees and undermines judicial and media independence is unacceptable.
“But this is no surprise from a Conservative Party that whipped its MEPs to vote in support of Viktor Orban’s government.
“Tim Montgomerie’s position as ‘social justice’ adviser is untenable and his comments show how far the Conservatives have moved away from traditional British values of fairness and equality.
“Boris Johnson must remove him immediately.”