British courts have allowed the publication of “particularly frank” letters from The Prince of Wales, which show him seeking to intervene in political decisions.

The British Prime Minister David Cameron is opposed to the release of the letters and may have them edited before they are handed over to The Guardian newspaper.

At stake is the concept that politics and the Royal Family in the United Kingdom should be separate, and evidence alleged to be contained in the letters may prove otherwise.

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The Guardian has battled for 10 years in the courts to see the 27 letters Prince Charles penned and sent to seven government departments in 2004 and 2005.

In a 2012 disclosure, the then-attorney general Dominic Grieve said the letters included the prince’s “most deeply held personal views and beliefs,” The Guardian reported, and may undermine his “position of political neutrality”.

But in the UK Supreme Court five-of-seven judges ruled in favour of disclosure on Thursday.

“We dismiss the attorney general’s appeal and the decision of the upper tribunal that the advocacy correspondence should be disclosed under the Freedom of Information Act … stands,” President of the court Lord Neuberger said.

A government spokesman said they would do “preparatory work” on the letters, which could mean editing or hiding sections.

“What we will be doing is complying with the judgment of the court but we will need to study and look at the best way in which to do that.”

And Mr Cameron, who described the court’s ruling as “disappointing”, said senior members of the royal family should be allowed to express their political views to the government.

“This is about the principle that senior members of the royal family are able to express their views to government confidentially,” Mr Cameron said.

“I think most people would agree this is fair enough.”

Mr Cameron pointed towards changing the laws to allow governments greater powers to veto freedom of information requests.

“If the legislation does not make parliament’s intentions for the veto clear enough, then we will need to make it clearer,” he said.

An aide to Prince Charles said Clarence House (the prince’s residence) was relatively relaxed about the publication of the letters but was disappointed the “principle of privacy has not been upheld”.