Council chiefs have dashed hopes that a harbour town could be turned into a tax-free haven like Monaco.

A local historian had hoped a law from the 14th century might exclude Queenborough residents from paying legal tariffs – including duty on wine.

Des Cross says the Isle of Sheppey town could have seen house prices rise into the millions as the ultra-rich relocated.

But legal experts at Swale council have poured cold water on the idea – saying that residents will still need to cough up their hard-earned cash.

An average band D property owner there currently pays £2,136.43 a year, never mind what they also lose in income tax, National Insurance and VAT.

Mr Cross’s hopes had rested on the Queenborough Charter, which dates back to 1369 when Edward III was on the throne.

The medieval document states the area is “exempt from taxes and tolls” – meaning locals could have seen a huge boost to their finances.

The 71-year-old had managed to track down a copy of the charter which is held at Kent Archives in Maidstone.

Luckily this was in English unlike the original in the Tower of London which is written in Latin or legal French.

Mr Cross said: “The charter is quite a powerful one. I don’t think I have ever seen one with as much in it.

“It gives Queenborough permission to have two markets and a fair but most significantly for the modern day it includes an exemption from all tolls and incredibly all taxes as well as all duty on wine.

“So if someone with deep pockets was to take a legal challenge the whole way, residents could suddenly find themselves with no tax liability.”

The Lordswood resident developed an interest in the town’s history when he was working as an accountant at the former Abbott Laboratories.

He first heard of the Charter around two years ago as the chairman of the Queenborough Harbour Trust.

He had needed council permission to launch a Saturday market on the promenade which sparked an interest in local bylaws.

Then around two months ago, the Charter came back to his attention when it was mentioned during debates about the Park Road and Queenborough library free car parks changing to pay and display.

While these plans were ultimately quashed, Mr Cross wanted to track down the ancient paperwork.

In Maidstone, he found a statute book from 1557, containing 150 individual vellum documents bound into a wooden cover including a copy of the Magna Carter and the Charter.

He said: “It was amazing to hold it after spending all that time looking for it.

“I didn’t think I would be allowed to handle it. To think that I was holding something that was first written in 1369 is amazing.”

Despite the Charter’s discovery, it will not turn the area – which the latest deprivation research found was among the poorest places in the UK – into the new Monaco, Isle of Man or Liechtenstein.

After some research, Swale council confirmed the charter had been superseded when the borough of Queenborough was reformed as a municipal borough in 1885.

Then the 1974 Local Government reorganisation meant the town formed part of Swale along with the rest of Sheppey.

However, despite the legal setback, Mr Cross is determined not to stop there.

He added: “Strictly speaking the council has no jurisdiction as this would have national significance as it exempts all taxes not just council tax.

“There will be another chapter in this story.

“The next step of the search is to go to the Tower of London to see if it’s still there or whether it has been transferred to the National Archives.

“I am hoping to get my hands on the original charter [to bring back to Sheppey]. It would be quite something for the town if we were to have it back as it would be quite the visitor attraction.”