The truth usually comes out, but unfortunately by that time the myth is usually so well implanted that it makes very little difference. With a new Thatcher myth being tacked on to the old one as we speak, lets look at some of the things we now know.
I could have done a list entirely on the Falklands War, her initial wobble, the attempted Argentinian attack on Gibraltar, the role of a squadron of light aircraft in confusing the task force etc etc, but these things make very little difference to the story.
I could also have done a list just on the Miners Strike, the BBC 'mistake' in editing the Orgreave footage to make it appear the miners started the trouble, the MI5 involvement, and so on, but I think most people who would listen already know these things.
So instead here is a very subjective list of what has come out since the Iron Lady left office.
1. Northern Ireland
John Stalkers' enquiry into the deaths of six terrorists suspects at the hands of a special RUC unit has never been published, but it doesn't really need to be. It's quite clear what we had here was a Death Squad in all but name.
What's less clear is what happened next. Certainly the RUC stopped shooting people, but suddenly the SAS started.
There is probably no single answer to what happened. Sometimes they may genuinely have been shooting in self defence. At other times it is clear SAS teams were deliberately put in situations where the IRA would attack them so that they could retaliate, such as the Loughgall Ambush. Then there were the so called 'mistakes', such as the three killed in Gibraltar.
How effective this was in fighting the IRA is open to debate, and it might well have been very effective.
What we now know though is that serious efforts were starting to be made towards bringing peace to the Province. John Hume of the SDLP and Gerry Adams of Sein Fein had already had meetings to agree a pan-Nationalist front, and Irish Taoiseach Charles Haughey was aware of this. Allegedly he tried to get Mrs Thatcher on board, but she declined. We don't know the details of these contacts, but we now know the offer of an IRA ceasefire was genuine.
Instead the Iron Lady proposed a Cromwellian solution involving the expulsion of the Catholic population and a redrawing of the border with the Republic. As this would potentially involve the ethnic cleansing of up to half a million people, her adviser were somewhat unenthusiastic.
So whilst Thatcher continued with her fantasies, British soldiers continued to die in a war that was ultimately all about nothing more important than, in the words of a friend of mine from Crossmaglen, what colour the post boxes should be.
2. The Secret Deal With Murdoch
When the Dodgy Digger's purchase of The Times in 1981 was not referred to the Monopolies Commission it raised a few eyebrows. The decision was taken by a minister, and the story, as reported in the Official History of the newspaper and repeated by Murdoch in TV interviews up to 2003, was that at the time Murdoch and Thatcher scarcely knew each other.
In reality he had been round for lunch at Chequers and was corresponding freely with the person he called "My dear Prime Minister".
So 'The Thunderer' became a mouthpiece of the Murdoch empire, not quite as vile as The Sun or the News of the World, but still a pro-Tory, pro-Israel, pro-USA instrument of propaganda.
3. Mark Thatcher In The Desert
In 1984 Mark decided to do his bit for the country by emigrating. He'd just been exposed by The Observer as a potential beneficiary of a project to build a £300 million University in Oman. Mrs T., who'd lobbied the Omanis to get the contract for the company, tried to brush the scandal off by claiming she'd been 'batting for Britain', but it had been a close call, so Mark was exiled.
However had the public known at the time what else Mark was involved in, it might have been Maggie who'd received her marching orders.
Getting to the bottom of the £40 + billion deal by which we keep the desert kingdom armed to the Fraud investigations have been opened and closed, and the deal was the subject of the only National Audit Office investigation never to be published.
What we do know though, is that right at the heart of Al Yamamah was Mark Thatcher.
He has denied receiving £12 in sweeteners, but what we do know is that he got very rich, very quickly and hasn't come forward to explain how. What we do know is that he acquired, via a front company based in Panama, a £1 million Mayfair flat and a £14,000 Rolex. All this from a deal negotiated by his mother.
If there was one scandal that could have brought down Thatcher whilst she was PM, this was surely it.