Secret letters sent by Prince Charles to government ministers in 2004 and 2005 will be published today.
Supreme Court judges ruled that Charles' correspondence with ministers - known as "black spider" memos because of his distinctive handwriting - will be released following a decade-long Guardian campaign.
The 27 letters to ministers in seven government departments will be published with some redactions to protect the personal data of people other than Charles.
Attorney general Dominic Grieve said the correspondence reflects Charles' "most deeply held personal views and beliefs".
The Government has battled to keep the letters out of the public eye but the Court of Appeal declared the veto unlawful last year - a ruling upheld by the Supreme Court judges in March.
David Cameron said at the time that the decision was “deeply disappointing”.
He said: "This is about the principle that senior members of the royal family are able to express their views to government confidentially. I think most people would agree this is fair enough."
The Prince of Wales and the Duchess of Cornwall are to make their first joint official visit to Ireland and Northern Ireland later this month.
The four-day trip is to "recognise the warm friendship and close cooperation that exists between the UK and Ireland".
In Ireland, the royal couple will meet Irish President Michael D Higgins for dinner, and attend the Sligo Races and other cultural engagements on 19 and 20 May.
In Northern Ireland, where they will be between 21 and 22 May, they will visit Belfast, with a stop at Mullaghmore, where the Prince's great-uncle, Lord Mountbatten, was killed in an IRA bombing in August 1979.
The royal family have donated to the DEC appeal to help the victims of the Nepal earthquake.
Both the Queen and Prince of Wales made personal donations to the appeal launched by leading UK aid agencies.
The Queen, and Charles and Camilla, donated undisclosed sums which will be used by the DEC Nepal Earthquake Appeal to support the work of its 13-member organisations.
The royal family have a long association with Gurkha troops who fight for the UK but are drawn from the men of Nepal, with Charles Colonel in Chief of The Royal Gurkha Rifles.
At the start of investiture ceremonies the Queen enters the room attended by two Gurkha orderly officers, a tradition begun by Queen Victoria in 1876.
The Supreme Court have reached an "unconstitutional decision" by allowing letters written by the Prince of Wales to government ministers to be published, Tory MP Jacob Rees-Mogg has said.
The MP for North East Somerset said the ruling would make it very difficult for Prince Charles to do his job.
"It is the job of the Prince of Wales to interest himself in what his majesty's government is doing that's his role, that's his job", he said.
The Supreme Court ruling on the release of letters written by Prince Charles to government ministers "is a good day for transparency in government", Alan Rusbridger, Editor-in-Chief, Guardian News & Media has said.
In a statement, Rusbridger said: "We are delighted the Supreme Court has overwhelmingly backed the brilliant 10-year campaign by Guardian reporter Rob Evans to shine daylight on the letters Princes Charles has been writing to ministers.
"The government wasted hundreds of thousands of pounds trying to cover up these letters, admitting their publication would 'seriously damage' perceptions of the Prince's political neutrality. Now they must publish them so that the public can make their own judgment.
"This is a good day for transparency in government and shows how essential it is to have a fully independent judiciary and free press."
Prime Minister David Cameron has said the Government will now consider how to release the Prince of Wales's letters following the "disappointing" ruling by the Supreme Court.
Cameron said: "This is a disappointing judgment and we will now consider how to release these letters. This is about the principle that senior members of the Royal Family are able to express their views to government confidentially. I think most people would agree this is fair enough.
He added: "Our FOI laws specifically include the option of a governmental veto, which we exercised in this case for a reason. If the legislation does not make Parliament's intentions for the veto clear enough, then we will need to make it clearer."
Guardian Editor in chief Alan Rusbridger today praised reporter Rob Evans for his 10-year campaign to allow the letters to be published.
Evans originally made an application under the Freedom of Information act to see the Prince's 2004 and 2005 letters to Government ministers.
When he was refused, he went to an Freedom of Information Tribunal who ruled they could be published in 2012.
But the Attorney General made a ruling preventing the publication of the letters by the Guardian.
Reacting to the Supreme Court's decision on the letters, Clarence House said it was "disappointed the principle of privacy had not been upheld".
The Supreme Court has ruled a series of letters written by the Prince of Wales to government ministers can be published.
The decision overturns an earlier ruling made by the Attorney General, which was upheld by the High Court, preventing the publication of the so-called 'Black Spider' memos.
Supreme Court President Lord Neuberger said there was a "fundamental composite principle" behind the court's reasons for dismissing the appeal.
He announced: "That principle is that a decision of a judicial body should be final and binding and should not be capable of being overturned by a member of the executive."
A Freedom of Information Tribunal had ruled in 2012 that the letters, so named after the Prince's distinctive handwriting and abundant use of underlining and exclamation marks, could be published but the Attorney General had prevented the publication.
The Supreme Court is set to rule whether letters written by the Prince of Wales to Government ministers should be made public.Read the full story ›