A cache of secret memos sent by Prince Charles to senior Whitehall ministers has finally been published, following a 10-year freedom of information battle between the Guardian and the government.

The letters, published at 4pm, reveal how Charles lobbied Tony Blair when he was prime minister to replace the Lynx helicopter in Northern Ireland. Charles complained: “I fear this one more example of our armed forces being asked to do an extremely challenging job without the necessary resources.”

He also complained to Blair in great detail about “increasing problems” affecting the dairy sector, complaining that the Office of Fair Trading had become “a serious obstacle to developing dairy co-operatives”. He warned Blair about the “anxieties which are developing particularly among beef farmers and to a lesser degree sheep farmers” as a consequence of the government’s mid-term review.

The government blocked the release of the letters, claiming their publication risked undermining Prince Charles’s “position of political neutrality”, which would not easily be recovered when he became king.

The government has spent more than £400,000 on legal costs to fight the battle.

The letters – 27 memos to and from the heir to the throne and ministers in seven government departments – relate to an eight-month period from September 2004 to April 2005, and were the subject of a Freedom of Information Act request by the Guardian journalist Rob Evans.

Charles’s correspondence was with ministers in the departments of business, innovation and skills; health; children, schools and families; environment, food and rural affairs; culture, media and sport; the Northern Ireland Office and the Cabinet Office.

Ministers described the memos as “particularly frank”. Charles’s letter-writing habit has been criticised as “meddling” by some, but the prince believes it is a legitimate part of his preparations to become king.

The letters emerged amid growing signs Prince Charles is planning to rule in a far more outspoken way than the taciturn Queen. Allies told the Guardian last year he planned “heartfelt interventions” in national life, while in 2013 his friend and biographer Jonathan Dimbleby said: “A quiet constitutional revolution is afoot.”

The Guardian can also reveal that, since the beginning of 2010, the prince held 87 meetings with ministers, opposition party leaders and top government officials. From the beginning of 2015 until the start of the election campaign he held meetings with, among others, David Cameron, the SNP leader, Nicola Sturgeon, the education secretary, Nicky Morgan, and Alistair Carmichael, then Scotland secretary, according to an analysis of court circular records by Republic, which campaigns for an elected head of state.

The Guardian editor-in-chief, Alan Rusbridger, said: “We fought this case because we believed – and the most senior judges in the country agreed – that the royal family should operate to the same degrees of transparency as anyone else trying to make their influence felt in public life.

“The attorney general, in trying to block the letters, said their contents could ‘seriously damage’ perceptions of the prince’s political neutrality. Whatever the rights and wrongs of that assessment, it is shocking that the government wasted hundreds of thousands of pounds of public money trying to prevent their publication. Now, after 10 years, we are pleased to be able to share the contents of his correspondence and let people draw their own conclusions.”

Freedom of information advocates immediately greeted the release of the letters as a significant moment.

“The release of the Charles memos represents a major victory for the freedom of information process, showing that ministers cannot block disclosure simply because they don’t like the result,” said Maurice Frankel, director of the UK Campaign for Freedom of Information.

Michael Meacher, a former Labour environment secretary who received private letters from Charles about policy, called for a new system of transparency around his correspondence with ministers when he becomes king to “remove public suspicion from the process”.

“A brief statement would be made the king has written to a minister and the subject would be obvious,” he said. “At least we would know he has been giving his opinions and some would say lobbying ministers.”

The supreme court ruled in March that the government’s attempt to block the letters’ release was unlawful. The government revealed in March last year that it had spent £274,481 on lawyers and, following the supreme court’s ruling in the Guardian’s favour, has since been ordered to make an interim payment of £150,000 towards the Guardian’s costs.

Since Evans’s original request to see Charles’s letters, the government tightened up the Freedom of Information Act to provide an “absolute exemption” on all requests relating to the Queen and the heir to the throne. That means such applications are now automatically rejected.

In 2012 the attorney general, Dominic Grieve, vetoed the information tribunal’s original decision to order publication of the letters warning they “contain remarks about public affairs which would in my view, if revealed, have had a material effect upon the willingness of the government to engage in correspondence with the Prince of Wales, and would potentially have undermined his position of political neutrality”.

There has been a decade-long legal battle by the Guardian involving rulings by 16 different judges stretching from a lowly information tribunal to the supreme court, the highest in the land.

Evans first lodged a request to see memos between Charles and ministers in various departments when the Freedom of Information Act was in its infancy, coming into effect under Tony Blair at the start of 2005. Blair later berated himself as “a naive, foolish, irresponsible nincompoop” for introducing it.

The requests were originally refused by Whitehall mandarins, who were supported by the information commissioner in a December 2009 ruling.

The Guardian fought on, appealing against that decision. After a six-day hearing at the upper tribunal, judges ruled on 18 September 2012 they should be released after all. But on 16 October 2012 Grieve used a ministerial veto to block the release. The Guardian challenged that again and won at the court of appeal on 12 March 2014. Lord Dyson, the master of the rolls, said Grieve did not have reasonable grounds for issuing the veto “merely because he disagrees with the decision” of the tribunal.

In a final bid to maintain secrecy, the attorney general appealed to the supreme court and lost in a judgment handed down by Lord Neuberger, its president, on 26 March this year.
(The Guardian)