Police have published an open letter to anti-arms protesters in an attempt to avoid a repeat of rioting outside a factory.

Smash EDO is holding a national march tomorrow as part of its campaign to close the EDO MBM Technology factory in Moulsecoomb, Brighton.

The movement claims the firm makes parts for weapons used in illegal military action.

An event on June 4 descended into violence with about 100 police officers involved, ten arrests and 20 people injured.

Tomorrow’s demonstration starts at Falmer railway station at midday. Publicity material for the campaign warns:

“This time we expect a show of force from the police. We will not let them stop us showing our anger at EDO MBM’s complicity in war crimes.”

The demonstration is called “Shut ITT”, which refers to the company that took over EDO at the end of last year.

Groups are expected to travel from Manchester, Nottingham, Sheffield, Hereford and Bath to take part in the march.

Sussex Police wrote to campaigners to talk about their plans for the rally but the approach was publicly rebuffed.

Smash EDO published an open response, which said: “The police say that they simply want organisers to come forward in order for them to plan a proportionate response.

“However, the police persistently attempt to target and criminalise people they perceive to be organisers.”

Sussex Police have taken the unusual step of publishing their own letter from Assistant Chief Constable Jeremy Paine in today’s Argus to renew the appeal for the group to speak to them.

Mr Paine wrote: “Concerns about what is perceived as a repressive stance by Sussex Police at demonstrations can be alleviated if there is a dialogue between the police and protest organisers.

“This is a key factor in ensuring we provide an appropriate level of policing.”

A force spokesman said: “We have made a number of attempts to contact the organisers because it enables us to ensure we can facilitate an orderly demonstration and provide a proportionate police response. Publishing our letter is a different approach simply to try to engage with those behind the demonstration so we can ensure it is peaceful.”

The force has been accused of overbearing policing of demonstrations in the past, with as many as 100 officers assigned to marches of 150 people.