When we started, it seemed nobody would talk - at least on the record. But that was three years ago, when Charles and Camilla's relationship was largely a matter for tabloids, gossip merchants and biographers of variable repute.
Steve Bradshaw, Panorama reporter
Looking back at the story of the Royal Marriage which he has followed for over three years
Now it's all so different - insiders and constitutional experts more willing to speak on the record. Our first programme made the headlines for Nicky Haslam's comment that Camilla's friends were already calling her "Queen", albeit in jest.
A Right Royal Shambles?
Sunday 2 October 2005
22:15 BST, BBC One
online at bbc.co.uk/panorama
But while making it, we also decided to check out the National Archives. We were looking for precedents - how a previous government had dealt with another controversial relationship, that of Edward VIII and Mrs Simpson.
Our search led to the discovery of legal advice to Prime Minister Baldwin that the King's wife is always de facto Queen whatever title she may use - advice still relevant today. We summed up the results of our research in the first of three programmes on the relationship.
What we didn't include then, something we discovered in the archives while looking at another precedent, was the putative marriage of Princess Margaret and Group Captain Peter Townsend in the 1950s. The government of the day was advised that members of the royal family couldn't marry in a registry office (other documents suggest they later offered a compromise, with Margaret keeping her title but losing the right to succession).
In February this year his advice suddenly became relevant. I was in a hotel lobby in Cambodia with the President of the World Bank when the Panorama editor, Mike Robinson, phoned with news of the planned marriage. Over a noisy phone line I suggested that there might be legal issues - and the reaction of the President's bodyguards (no slouches in finding out what's going on round them) reminded me this was a story worth telling.
Next day researcher Kath Posner revisited the Archive and found that a subsequent government in 1964 had taken the same position. So we made a second programme that weekend, describing these legal doubts, but pointing out the Human Rights Act might allow a way out. (The latest legal position is described in the Lord Chancellor's subsequent statement and a separate article on this site).
As it happened, the legal issues proved to be only one of Clarence House's subsequent problems. There issues with the Church, the press, the law and Buckingham Palace.
And these are what producer Alice Perman and I look at in this latest programme, with the help of some of those in the know. Obviously the details of any conversations between the Archbishop of Canterbury and the couple are a private pastoral affair. But it's clear that Charles and Camilla's past led to a judgement that a church wedding would not be compatible with Church guidelines.
That in turn - coupled with the leak of the news - led to the series of misunderstandings and gaffes we detail in A Right Royal Shambles?
None of these problems seemed finally to spoil a successful outcome on the day. But they do remind us that this royal marriage - unlike most others - has raised real issues of public policy. And may yet do so again.