This was Hitler's favourite song. Or rather it wasn't.

Last night I was due to climb every mountain – well, head down the Lower Bristol Road – and go to Bristol to watch The Sound of Music onstage.

It was amazing to me the effect this had on some of my colleagues when I casually mentioned the news. As it is not the sort of music that people usually associate with me, I expected to be ribbed mercilessly but within minutes of mentioning it several hard-bitten hacks were heard to be singing about lonely goat herds and troublesome nuns.

It is just one of those shows that seems to ‘get’ everyone.

Having thought I’d done well to keep my credibility intact, however, I then completely ruined it with a chance remark. Someone said that their favourite song in the film was Edelweiss and I retorted: “Well, you may like it less when you realise it was Hitler’s favourite song”.

“Are you sure?” said someone.

“I am,” I replied. Firmly. Ish.

Two minutes later I was peeling egg off my face when I realised (or rather Wikipedia proved to my ‘doubter’) that the song was actually written in, err, 1959. I then weakly tried to regain my wrecked credibility in the ‘things-you-don’t-know-about-Hitler’ stakes by saying: “Ah well, did you know he designed the Volkswagen Beetle?”

Wikipedia – which you soon realise can be your biggest enemy as well as your best friend – found that this was nonsense too. The dictator had asked in 1933 for a ‘people’s car’ to be designed but his pencil never touched paper.

So once again I’d fallen for an urban myth.The truth is we can often fall of these and that is why Stephen Fry’s QI is an invaluable way of stopping us from repeating “truths” which are actually nonsense.

So, can I stop all of you from making similar mistakes by assuring you, for example, that Humphrey Bogart never said “Play it again Sam” in Casablanca, Sherlock Homes was never quoted in the novels as having said “elementary, my dear Watson”, Captain Kirk never uttered the line “beam me up Scottie” and Darth Vader never said the phrase “Luke, I am your father”.

And, to save you wasting a good ten minutes of your life hearing a long, urban myth story, can I assure you that David Beckham NEVER paid off somebody’s mortgage so his son could have a party at Alton Towers. If the elements of that story sound at all familiar then I’m not surprised because I’ve been told it in three different offices over the last few years or so by sincere people who claim they even know whose house was paid off by the generous footballer. But it never happened.

Trust me. I’m a journalist.

The only problem with de-bunking urban myths is that they do take some of the fun out of life. I love the story of how NASA apparently spent millions trying to develop a pen that would write upside down in space while the Russians just used a pencil. But, sadly, it wasn’t true.

Just like the moon landings, in fact.