Essex Police have responded to controversial plans to build two prisons the size of a town on the former WWII Wethersfield airbase, arguing that this will prompt an increase in organised crime.

The Stop Wethersfield Airfield Prisons (SWAP) campaign has been urging the Ministry of Justice to abandon the plans, which would involve a category B and a category C prison being built in a semi-rural area.

A petition reached 10,000 signatures in May this year, with the help of wildlife presenter Chris Packham.

In their response to the MoJ's public consultation, Essex Police said: "The development of two new prison establishments is likely to attract additional Organised Crime Group (OCG) related activity such as staff infiltration, throw overs (the process of introducing controlled drugs and mobile phones into prison), serious violence amongst gangs and organised crime groups and the progression of organised crime activity within the confines of the prison.”

The police also expressed concern that the development would attract a higher number of people to the area, including staff, visitors, deliveries, and prisoners who are released on remand, on probation or having completed their sentence.

They said: "This influx of activity will inevitably lead to an increase in the number of calls for police service in response to reports of crime and antisocial behaviour.

"Whilst it is not possible to place a metric on the number or type of crimes or behaviour at this point, the sheer scale of the development would suggest the need for a considered policing response to avoid critical impact on the policing response in the wider North Essex area, including the city of Chelmsford and towns including Colchester and Braintree.”

The police also argued that the road network in the surrounding area is not suitable to cope with an increased level of traffic during the construction or post-opening phase of the project.

SWAP chair Alan MacKenzie added: "Essex Police has highlighted the likely influx of Organised Crime Groups into Braintree as a consequence of the prisons being built, as well as the increased dangers on the rural roads as a consequence of construction traffic and the heavy goods vehicles which would blight the district forever more.

"The police rightly say who is going to pay for the extra resources that this crimewave and increased traffic accidents will require – the answer is local taxpayers."

In the consultation document, the Ministry of Justice explained that they had committed to creating 18,000 additional prison places by the mid-2020s.

They said: "Our plans, if successful, would bring many benefits to the local community, such as hundreds of jobs during construction, careers within the prison sector and an increased spend in local businesses."

A Ministry of Justice spokesperson added: "We have not made a decision regarding submitting a planning application for RAF Wethersfield as a new prison. We will continue to inform and consult local residents on any future plans for the site."