Sadiq Khan plans to write to Amber Rudd, the Home Secretary, urging her to make supporting all factions of Hezbollah illegal in Britain.

Both Conservative and Labour figures have lobbied for a ban on the political wing of the terror group. Its official terrorist wing is already proscribed in this country.

Mr Khan’s expected letter comes after Hezbollah flags were spotted at last month’s Al-Quds march in central London.

Mr Khan said: “I share the concerns of the Jewish community about support shown for Hezbollah, which is an illegal, proscribed and antisemitic organisation.

“Antisemitism or hate crime of any kind has no place in our city, where we don’t just tolerate diversity, we respect and celebrate it.

“I remain in contact with the Met Commissioner about this issue, and will be writing to the Home Secretary to make strong representations on behalf of London’s Jewish communities about their legitimate and understandable concerns.

“I will continue to work with the Met and communities across the capital to do everything in my power to crack down on extremism and ensure London’s Jewish communities feel safe and secure in London.”

Mr Khan’s decision comes two weeks after a heated exchange with Tory GLA member Andrew Boff.

Mr Boff asked: “Will you write to the Home Secretary and say that we need to clarify what is a banned and not-banned organisation in order to assist policing such demonstrations in the future?

“Will you, Mr Mayor, look after the interests of the Jewish population of London?”

The Conservative Friends of Israel, the Labour Friends of Israel and the Jewish Labour Movement have called for an outright ban of Hezbollah.

Andrew Dismore, Labour's London Assembly member Barnet and Camden,  said: “I have spent over a decade campaigning for the complete proscription of Hezbollah, as I believe the distinction made between the ‘political’ and ‘military’ wings to be utterly bogus.

"I am pleased the Mayor has recognised my work on this and has agreed to write to the Home Secretary. This ban is long overdue."

Marie van der Zyl, Board of Deputies vice-president, said: “This is a welcome step by the Mayor which is fully supported by the Board of Deputies.

"Hezbollah itself does not distinguish between its military and political wing which is one and the same. The government urgently needs to follow the example of the USA, Canada and the Arab League by outlawing Hezbollah in its entirety.

"It is a terrorist organisation - end of.”