Prince Leonard, founder of the Hutt River Province in Western Australia, has died aged 93.

The self-proclaimed prince, who had a long battle with emphysema, was admitted to hospital in Geraldton at the weekend with a severe chest infection. It is understood he died on Wednesday morning.

Leonard Casley set up the legally unrecognised independent state at a 75 sq km property in WA’s Mid West region following a row over wheat production quotas in 1970.

He abdicated to his youngest son Graeme in 2017.

While it has never been recognised by the state or commonwealth governments, the Principality of Hutt River received a letter from Queen Elizabeth II in 2016 on its 46th anniversary.

The tourist attraction even has its own postage stamps and currency, about 10,000 non-resident citizens and a treaty with indigenous land owners. But the “royal” family was hit with a $3 million tax bill in 2017, with Prince Leonard ordered to pay $2.7 million and his son Arthur to pay more than $240,000.

WA Supreme Court Justice Rene Le Miere dismissed their arguments as bizarre, irrelevant and gobbledygook.

“Anyone can declare themselves a sovereign in their own home but they cannot ignore the laws of Australia or not pay tax,” he said at the time.

Perth Now quoted the Principality’s Acting Minister for Electronic Communications Lord Steven Baikie, who said the border will be closed for three weeks and no visitors will be admitted.

A service will be held in the principality at a later date.

Prince Leonard is survived by seven children and “many grandchildren and great-grandchildren”.