March for England is threatening to return to Brighton and Hove’s streets this summer unless a councillor who branded soldiers “hired killers” resigns.

The nationalist group made the threat after Councillor Ben Duncan, a Green Party member who represents Queen’s Park, sparked outrage when he tweeted: “Armed Forces Day has certainly brought the hired killers on to the streets of #Brighton today. Hard to explain to my son.”

The right-wing March for England (MfE) parade brings Brighton and Hove to a standstill the Sunday after St George’s Day each year and costs the police hundreds of thousands of pounds.

MfE bosses are demanding that Ben Duncan apologises “properly”, resigns and donates £1,000 to a forces charity.

A spokesman for MfE said: “Ben Duncan should resign and him or the Green Party donate £1,000 to a forces charity to make up for the grief his stupid comment has caused to the families of the fallen and our serving and ex-forces.

“The Greens constantly complain about the cost of our parade in Brighton so simply resign, apologise and make a donation to a forces charity and this will be an end to it.

“People are fuming over this statement from him.”

A post on a blog, confirmed to be accurate by the MfE spokesman, said demonstrators will return to Brighton “sometime in August” and the administrator of their Facebook page posted “you might just see us before April” next year.

A council spokesman said: “Organisers of demonstrations are not required to seek permission from the council or police.

“However we do advise organisers to liaise with the council, police and emergency services.

“In the past March for England have done this.”

A Sussex Police spokeswoman said: “Organisers of demonstrations are not required to seek permission from the council or police but do need to give the police a minimum of six days’ notice of an intention to process.

“We do, however, advise them to notify and liaise with the council and police at the earliest opportunity to discuss their intentions.”

A spokesman for the Brighton and Hove Green Party said they were aware of the threat. Coun Duncan is currently undergoing disciplinary proceedings from his own party over the tweet, the latest in a series of controversial statements he has made. He has now closed his Twitter account.