YOUR family's history probably isn't something you think about on a daily basis, but wouldn't you love to know more about your ancestral line?

Many of us have heard tales of brilliant, adventurous or just plain bad relatives, often from grandparents during our early years, but like Chinese whispers, such folk stories have obviously grown increasingly exaggerated over time.

If you have enough patience, it's possible to discover hard facts and dispel fictions about those who came before you, and for this series of Who Do You Think You Are? (BBC2, 9pm, Tuesdays) a number of celebrities have unearthed fascinating information about their own clans.

TV presenter Jeremy Clarkson explores his family tree and learns of a distant relative's entrepreneurial success and subsequent disaster.

Jeremy's initial efforts prove a little disappointing and he makes no secret of his devastation to discover several generations of his family lived, worked and died in one small area.

"Take the Clarkson name back to its Yorkshire roots and they all come from within a few miles of each other,"he explains. "I'm the product of 200 years of inter-breeding. I'm surprised I haven't got one eye."

However, further delving uncovers a connection to another clan he finds difficult to comprehend. Jeremy's great, great grandfather, Caleb Kilner, was the inventor of screw-topped, rubber-sealed jars. Airtight storage for preserving food is now taken for granted, yet such items didn't exist until the 1890s when the world-renowned 'Kilner jar' went into production.

Unfortunately, the successful business ran into trouble in the late 1930s and, despite having a staff of several hundreds for decades, went bust.

"Selfishly, I'm quite keen to find out what happened to the money," Jeremy says with a wry smile. "Is there somewhere a dusty piece of paper that says I'm owed £48billion?"

The larger-than-life and often outspoken car enthusiast is happy to admit he has always taken a keen interest in cash, so the possibility of being heir to a fortune is obviously one he wants to look into. However, in recent years, his career has been a lucrative one, so the need to get his hands on long-forgotten funds isn't exactly essential - although JC does worry his success won't last.

"I always think that tomorrow will be the last day of my career so you have got to go and go and go as fast as you can and do as much as you possibly can before it all goes wrong.

"In TV no one lasts forever," he says prophetically "And it was such an honour and a privilege and so amazing that it happened in the first place that it is daft not to capitalize on it now.

"These pop stars who spend all their money when they are 20 are idiots. How daft have you got to be to think this is going to last for ever?

"I know it is a terrible cliche," he sighs, "But I really never do anything except work. My ambition has always been to get the children's school fees paid for and the mortgage paid off, then my hair can fall out, my teeth can turn yellow and it won't really matter."

Despite his fears, Clarkson looks set to be on the box for a good few years yet, not only making guest appearances on shows such as this, but also headlining entire series, including Top Gear which has also made a welcome return to our screens.