After one particularly frustrating overseas trip last year - Prince Charles and Camilla's visit to Turkey - I got so fed up at the lack of anything approaching a real story that I tried to find out just exactly how much it had all cost and what had been the benefit to Britain.

I discovered that the Foreign Office, which asks the Royal Family to go on these visits to help smooth relations with key nations, does not routinely keep an account of the cost of these trips and provides no account to Parliament about what they achieve or fail to achieve.

Five months after being passed around the houses by various officials at Clarence House, Buckingham Palace, and in Whitehall, the Foreign and Commonwealth Office has now released papers to me under the Freedom of Information Act.

Among the papers are reports sent back to the FCO by British ambassadors or high commissioners who helped to host the last few visits undertaken by Charles and Camilla.

In addition to revealing an interesting tale about a diplomatic row over Charles's visit to a seedy red light district in the Ugandan capital Kampala (to see various charities, including one for reformed prostitutes), they do actually give some insight into the official view of the visits. The reports, almost inevitably, put a positive spin on everything.

There is no mention, for example, of the fact that half the Commonwealth leaders snubbed Charles and Camilla by deciding not to bother to attend a banquet in their honour in Uganda.

They have also been censored to take out anything too embarrassing or personal but they do provide some useful background which, in my view, the Foreign Office should publish on a routine basis so that MPs and the public can understand better the work the royals do.

"Some reflections on royal visits, at least to the UAE," wrote Britain's ambassador in Abu Dhabi, Edward Oakden.

"Despite the extra load which they bring, they reach parts that other visitors cannot, and so make a unique contribution."

In Kuwait a senior British diplomat described how Charles and Camilla's visit had improved the already warm ties with the ruling family, leading to the chance of new commercial opportunities for British energy firms, a united front to combat climate change, and greater encouragement of young entrepreneurs.

"Overall, I am most grateful to Their Royal Highnesses for the time and effort they expended in Kuwait (and in particular for the attention they paid to Embassy staff, who worked hard for the visit’s success). The results achieved …..could not have been reached by anyone else," the diplomat wrote.

Much of their reports focus on the media attention given to these trips, which in many nations is much more respectful and unquestioning than in Britain, something that clearly irritates our diplomats.

When Charles flew to America to receive a prize for his environmental campaigning, there was, perhaps not surprisingly, some controversy about whether running up a bigger carbon footprint was the right thing to do.

So I was amused by one unnamed British diplomat, presumably the then ambassador Sir David Manning, who wrote: "As I told the typically grudging and carping British media, we should be proud of anyone who wins an award of this kind from Harvard. The university is not in the business of flattering princes."

While in my view the Royal Family do a good job for Britain, it's right that we in the media continue to examine their activities forensically. However, I do agree very much with the ambassador in the Emirates who wrote about the relentless attention of the press and the "need actively to feed them substance to make it harder for them to write trivia: in future I wonder if we should put even more effort into this."

Yes, you should, sir. And one way is to give much more information about the targets, successes and failures of each of these missions.