A jury has heard how a father-of-two made a "viable" explosive device in his flat after consulting an AI chatbot about prepping for disasters.

Ben Banham, 38, of Rokescroft in Pitsea, Basildon, also wrote a journal in which he referred to a "Project Prometheus", of which the aim was to defend his family's home using gunpowder.

More than 80 addresses were evacuated on 10 March after bomb disposal teams found a black cylindrical device with a wick or fuse in the top in Banham's three-bedroom property, where he lived with his wife and two young sons.

Banham admits possessing explosives but denies intending to endanger life or cause serious injury.

Opening the prosecution at Basildon Crown Court, Tessa Shroff told the jury how "over time, Banham had become concerned about events in the world and how they might impact on his family life".

He had set up a "store room", stocking up on staple products for his family including food, drink and survival items for hunting including sharp metal arrows.

Banham - who worked for Asda - described himself as a "prepper" in conversations with ChatGPT, telling the chatbot he had been prepping for about two years, the court was told.

Other messages in September 2025 included his search for suitable locations to camp should he need to evacuate his family, whether France was - at that time - preparing for mass casualties, and also how firearms such as flintlock muskets worked.

He had also researched weapons such as crossbows and air pistols on his phone.

The jury heard how in a journal entry on 1 July 2025, Banham wrote: "The goal of Project Prometheus is to manufacture high quality black powder [gunpowder] that, in the event that it is needed, can provide an effective defence of the family home."

The entry continued: "I aim to achieve this not through direct injury caused, but rather through shock and awe tactics, loud bangs and blinding flashes can disorientate and deter any threat.

"However this alone may not be sufficient, so I have also decided to design a device that can cause injury or death to be used as a last resort, but this is a long way off - first we must achieve the basics."

As well as the explosive device, officers discovered a number of containers with gunpowder inside, as well as an invoice for a kilogram of sulphur, bulk-bought matches and a number of fireworks, when they raided Mr Banham's flat.

"Mr Banham's behaviour had at some stage been escalating," Shroff told the jury.

"What may have started with unusual but still legal activities, such as learning how to hunt or survive in the wild, slowly became a desire to learn about - and then make - gunpowder.

"He developed.. a frustration about what the law does and does not allow you to have - and his frustration led to action," she continued.

"He placed orders, he made purchases and he conducted experiments. He did so in his home, close to where his young children no doubt were."

"People cannot be sat in the privacy of their homes - completely unbeknownst to the emergency services, to the general public and to those who protect us - creating or perfecting potentially deadly weapons or substances 'just in case'," Shroff said.

Banham is charged with possession of an explosive substance with intent, and the trial - which is expected to last up to two weeks - continues.

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