Fireworks with explosive power equivalent to two sacks of potatoes-worth of gunpowder could have destroyed the Ramsgate depot where they were stored.

Fortunately the business, started by entrepreneurs Grant Smith, 35, and Jamie-Lee Bailey, 26, fizzled to a halt after a Kent Trading Standards officer bought fireworks from them.

He found pyrotechnics stored in open boxes in a storage unit open to the roof and lighting. They had been advertised on posters and Facebook.

Andrew Price, prosecuting, told Canterbury Crown Court: “If there had been a fire, the ignition of the fireworks could have been catastrophic. The nearest water sprinkler was not above the unit.”

“These were simply ridiculous conditions for the storage of fireworks” - Trading standards manager Mark Rolfe

Smith, from New Barnet, London, and Bailey, of James Close, Ash, had previously admitted supplying and storing explosives without a licence.

The prosecutor said items had been protruding from the storage unit at Priory Self Store. A fire would have put people working at the premises in danger and could have destroyed irreplaceable items being stored there.

A raid last autumn by police and Kent County Council’s trading standards had found fireworks in 23 boxes, selling for between £300 and £500.

Trading standards manager Mark Rolfe had said at the time that a single spark could have caused an explosion big enough to destroy the depot and that the amount of explosives involved was the equivalent of “two wholesale-size sacks of potatoes of pure gunpowder.”

He said: “These were simply ridiculous conditions for the storage of fireworks.”

The court heard that the chemical destruction of the fireworks would cost £325.

Sentencing Smith to six months in prison, suspended for two years, and Bailey to a community sentence for a period of supervision, judge Nigel Van Der Bijl described the potential of the offences as “extremely dangerous” and “disastrous”, acknowledging that the pair had not realised this at the time.

Simon Taylor, defending Smith, said the “hard-working family orientated” man had made a mistake he did not realise, involving criminal liability and culpability. No harm had actually been caused. He had learnt his lesson.

Smith had been trying to make a living after his foot had been run over and broken when he had been working in the building industry. He did not understand licensing and took responsibility.

Danny Moore, defending Bailey, said she had said: “If I had allocated five seconds of head space, I would have thought about whether he had the correct licence.”

Police and trading standards put an emphasis on the safety of fireworks and their sale at this time of year.

Anyone who needs to store large quantities of fireworks, or anyone who has concerns about illegal storage, can check with trading standards that the venue is appropriate and safe.