The Home Secretary, Amber Rudd, has refused to close a legal loophole that allows demonstrations in support of the political wing of Hezbollah, while its military wing is banned.

The Mayor of London wrote to Ms Rudd after the Al Quds march in June to support Jewish organisations and others who were angered by Hezbollah flags on the streets of London.

A source close to Sadiq Khan said he is “extremely disappointed” that the Home Secretary has refused to act.

In a letter seen by the JC, the Mayor wrote in July that extremist groups were “exploiting a loophole” insofar as they were allowed to carry Hezbollah flags on the basis of supporting its political arm.

He wrote: “I am writing to make strong representations on behalf of London’s Jewish community and others who have legitimate concerns about the Al Quds Day March.

“Hezbollah is an illegal, proscribed organisation, yet many perceive that it was actively celebrated during the Al Quds Day March.

“I would appreciate a response from the Government that acknowledges the hurt that is felt and your plans to close any loophole."

In her response, dated September 4, Ms Rudd refused to issue an outright ban, instead saying it is only illegal to carry a Hezbollah flag if the “context and manner” in which it is done clearly demonstrates support for the group’s banned faction.

She wrote: “The group that reportedly organised the parade, the Islamic Human Rights Commission, is not a proscribed terrorist organisation.

“This means they can express their views and demonstrate, provided that they do so within the law.

“The flag for the organisations military wing is the same as the flag for its political wing. Therefore, for it to be an offence under Section 13 of the Terrorism Act 2000, for an individual to display the Hizballah flag, the context and manner in which the flag is displayed must demonstrate that it is specifically in support of the proscribed elements of the group.”

In the wake of the Al Quds Day march, the Conservative Friends of Israel, the Labour Friends of Israel and the Jewish Labour Movement all 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."