He had been in Moscow, where he met with Errol Musk, the father of billionaire Tesla founder Elon Musk.

The former English Defence League founder, whose real name is Stephen Yaxley-Lennon, also attended the annual Kremlin-backed economic forum, described as Russia’s answer to Davos.

In a statement, the Met said: ‘Officers stopped a man in his 40s at Heathrow Airport at around 5pm on Saturday, 13 June, following his return to the UK from Russia via Turkey.

Read more: Tommy Robinson detained at Heathrow under terrorism act after Moscow trip with Musk’s dad