OVER the years comedian Mark Steel has travelled the country visiting and researching towns as part of his Radio 4 series and stand up show Mark Steel's In Town.
But recently a different type of research has been occupying his mind - that of finding out more about his biological family.
The results - which he readily admits are both surprising and "mad" - have been turned into his latest stand up show, Who Do I Think I Am, which he is currently touring in venues around the country.
He is bringing his revelations to Blackheath Halls on April 30 and promises it will be both "fascinating and funny".
"You couldn't make it up actually," he laughs as we chat ahead of the gig. "In fact it's ridiculous and a bit bonkers, like a really really bad Jeffrey Archer novel!"
Mark, who was born in 1960, was adopted a few days after he was born, something he says he has always known. It was by all accounts a close family and growing up in Swanley he was never interested in finding his birth parents.
That is until his son Elliot was born nearly 20 years ago. It was at that point that he began to think differently.
"I always knew I was adopted so there was never any issue about it - in fact the whole thing was more fascinating for other people than it was for me," he tells me.
"So, I'd never been bothered but when Elliot was born, well it's a big thing isn't it, and I thought my mum might be wanting to know how I was."
However, it turned out she didn't. When he finally traced her she didn't want to know or even meet Mark but she did tell him about his father. And it was at this point that the astonishing details of his birth parents started to emerge.
He doesn't want to give away too many spoilers but it turns out that Mark - well known for his left wing leanings - is the son of Joe, a multi-millionaire former Wall Street trader and the world backgammon champion.
Joe also used to gamble at the famous Clermont Club in London alongside one Lord Lucan and also had connections with the likes of capitalists Tiny Rowland and James Goldsmith, father of Zac.
The irony of all this is not lost on Mark.
"It is just ridiculous," he admits cheerfully. "I was surprised to find out all this stuff about my dad but not disappointed.
"The starting point of the show is finding my mum but from there on in it just gets more bizarre.
"It's quite peculiar and the show is about the whole madness of it. It's a very strange business and finding out all this stuff about my dad was, well, it's fascinating and just mad.
"You won't believe the ending - there are lots of juicy revelations", he adds chuckling.
"Like that £10million I've got in an offshore account. Despite being asked several times it turns out I did have that money all along... !"
Jokes aside he says he wouldn't be at all surprised if his father has shares in the Panama off shore tax haven that is currently exercising the interest of people across the country.
"I don't want to give you all the details, you will have to come and see the show to find out what happens," he says.
"However, there is no question my dad's got considerable sums of money stashed away in tax havens. He's considerably wealthy - he was the world backgammon champion afterall!
"Zac Goldsmith's dad was one of his closest friends. I wrote to Zac actually just before Christmas and said 'I know you're really busy but here's a fascinating thing....' but he never wrote back..." he muses.
The process of finding out more about his biological parents turned out to be longer than he expected and it has taken the nearly 20 years since Elliot was born for Mark to find out these details about where he comes from.
In fact it was only about five years ago that he first made contact with his mother.
"I would do the things you do and write to people and go to register offices and then do something else and come back to it," he says.
"So it was done in fits and starts but eventually it came together although my mum didn't want to be found."
But during his research he uncovered other bits of his biological family and these other various strands have their own mysteries, so his work is ongoing.
"Every time I do more research it gets more absurd and far fetched," he chuckles. "There is another side of my family which is equally fascinating so there is all that to discuss.
"They turn up in the show and whether I meet my dad is another point that emerges. I'm sure if I wrote this as a story people would say I'd made it up or think it was written by someone like Jeffrey Archer and wonder how he got away with it.
"He would have called it something terrible like Beg Borrow Or Steel," he adds laughing.
"It's just very funny and actually I wouldn't have written it or inflicted it on people as a show if it wasn't. Someone wrote after one show saying I was brave but it's not brave. It's not a journey and it wasn't cathartic either - it was just fun to find out and talk about."
He admits though that his views on the nature versus nurture debate have changed somewhat.
"Before I started this whole thing I was of the opinion that you are just who you are rather than anything to do with genes, but now I do think it's a bit of both," he says.
"But I'm not of the opinion that somehow your natural blood relatives are your own responsibility."
And he says his two children have not given Mark's quest anything more than a passing interest.
"My lad is very much of the opinion that it's those who've brought you up who are family and who are important," he says. "In fact neither of my kids have much interest in it to be honest."
He hasn't taken their indifference personally and has instead been pleased at the positive reactions he's had from his audiences. And he's looking forward to bringing the show to Blackheath, a place he says he is very fond of and knows well given that he's made his home in nearby Crystal Palace for many years.
"It's lovely but a bit peculiar," he says. "Lots of people say that London is made up of a series of villages but Blackheath really does go out to some lengths to convince people it's a village even though it's half a mile from Deptford!
"It's a lovely part of South London though and it will be nice to be back and bring the show here.
"It's an entertaining show and I'm pleased with it," he adds. "It was difficult to write as to put anything together for a two hour show is not easy, but my parents have bequeathed me this funny story so I'm blessed with that."
Mark Steel Who Do I Think I Am is on at Blackheath Halls on Saturday, April 30. Visit http://www.trinitylaban.ac.uk/blackheath-halls for full listings.