The Brighton May Day Smash EDO protest cost Sussex police more than £310,000.

The massive bill to the taxpayer followed chaotic scenes as 1,000 protesters, many with their faces masked, brought central Brighton to a standstill.

The sum - revealed ahead of a Sussex Police Authority meeting this week - would be enough to pay 14 newly-qualified police constables for a year.

Sussex Police have described the impact of the march on the city as “minimal”, despite hordes of protesters attacking fast food chains and invading residential neighbourhoods.

The “May Day May Day Street Party Against War and Greed” took place on Bank Holiday Monday, May 4.

Organised by Smash EDO - an anti-war group campaigning to close the EDO MBM Technology arms components factory in Moulsecoomb - it followed sometimes violent confrontations at two previous demonstrations in the city.

The event put Sussex Police under the spotlight because it was the first large-scale protest held after the G20 summit in London.

Throughout the operation police had a documentary film crew and members of Sussex Police Authority embedded with senior officers to monitor the way events were handled.

Officers were drafted in from the Hampshire, Kent and Thames Valley.

Marchers took over the roundabout at the Palace Pier, before marching through North Street, Queens Road, Trafalgar Street, London Road, Ditchling Road, Ditchling Rise and Preston Park.

It eventually petered out back in the city centre with gatherings near St Peter’s Church and at the Palace Pier.

At its peak police estimated there were 1,000 people involved - while Smash EDO estimated 2,000. Two officers were injured, there were two reports of criminal damage and four people were arrested.

Chief Constable Martin Richards is due to present a statement to Sussex Police Authority on Thursday.

It reads: “Despite strenuous efforts from Sussex Police no organisers for May 4 were willing to come forward and as a result little was known about protester intentions or numbers.

“A police operation was put in place with the first priority being to minimise the risk of harm to the general public and to those involved in or affected by the event.”

Sussex Police are still waiting for overtime claims from officers before calculating the total cost but so far it has reached £310,000.

A demonstration at the EDO factory in Home Farm Road, Moulsecoomb, in October last year cost £50,000 to police.

A report from magistrate Alan Price, Sussex Police Authority’s lead member for operations, described the operation as a success.

Councillor Ted Kemble, Conservative council cabinet member for enterprise, employment and major projects, said the protest had not damaged the city economy.

He said:” From the soundings I have taken there was very minimal disruption to the economic welfare of the city.”

No-one from Smash EDO was available to comment yesterday.