His visit comes amid heightened tensions between Iranian authorities and the UK after Iran’s judiciary labelled the ambassador “persona non grata” and called for his expulsion from the country.
However, the Foreign Office has said Mr Macaire's visit "has been planned for quite a while" and insisted he intends to return to Tehran in the coming days.
"It is quite normal for our ambassadors to come back to London to have meetings here," a Foreign Office spokesperson said.
Mr Macaire was arrested in Tehran on Saturday over his attendance at a vigil for the 176 people, including four Britons, who were killed when Iran accidentally shot down a Ukrainian jet.
Iranian protesters on Tuesday burned an effigy of the ambassador alongside UK and US flags at a demonstration by members of the Basij, a militia which is part of the Islamic Revolutionary Guard Corps (IRGC).
Mr Macaire angered Iranian authorities over the weekend by attending a vigil for the crash victims, in which demonstrators condemned the downing of the Ukrainian airliner.
The UK ambassador has said he left the event after protests broke out, but Iran’s foreign ministry summoned him on Sunday to explain his “illegal and inappropriate presence” at the event.
Iran admitted last week that it shot down the Ukrainian passenger jet, killing all 176 people on board, but said the incident occurred by accident as the result of human error.
Authorities had initially denied involvement in the crash, which happened shortly after Iran responded to the US killing of general Qassem Soleimani by launching ballistic missiles at two bases in Iraq which house US troops.
An official from the IRGC said a “bad decision” to open fire on the plane had been made after forces mistook it for a cruise missile.
Dominic Raab, the UK foreign secretary, has condemned Mr Macaire’s arrest as “a flagrant violation of international law” and said he has received no formal indication that the ambassador will be expelled.
“It would be deeply regrettable if that were the case,” he told the House of Commons.
“We need to keep the diplomatic channels open, and futile gestures like that are not going to resolve the problems that the regime in Tehran face.”
Additional reporting by PA
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