Kate Humble gets to grips with her ancestry in next week’s Who Do You Think You Are? screening on BBC1 on Wednesday, July 29 at 9pm.

Sounds like it was quite an experience for you?
“For a start you are, to all intents and purposes, kidnapped by the production team – you have no control over where you’re going, what you’re doing, or who you’re meeting, you know nothing! I was given one phone number, told to pack a bag with warm stuff just in case, and possibly a passport…”

Were you at all worried about what you would discover?
“At the beginning, I thought, we’re kind of related but it’s all pretty tenuous, these people are nothing to do with me really, we share some genes but we also share a lot with chimpanzees, and you can’t be responsible for them either. If they turn out to be thieves and murderers that’s not my fault, I’m trying to be a decent person!”

Did you think it would be an emotional experience?
“My husband (TV producer Ludo Graham) said, ‘you cry at everybody else’s Who Do You Think You Are, you’re going to be completely hopeless at your own!’ I said, ‘No, its OK I’m not going to cry’. Of course he was completely right. I sobbed all the way through…”

You started with your paternal grandfather, test pilot Bill Humble who you knew only briefly?
“He wasn’t a friendly grandfather in a knitted jumper, handing out Werther’s Originals, but a naughty man who used to pour me enormous gin and tonics! I admired him because he was so unconventional, but I didn’t really know anything about him.”

How was it meeting his old co-pilot, Captain Bill ‘Winkle’ Brown.
“He said, ‘Do you know the man flying in the flying jacket is? It is a photo of your grandfather?’ I thought, how can you tell? And he said, ‘Well he’s not wearing a helmet and your grandfather never wore a helmet, he’s too vain!'”

What was it like watching footage of him from the 1930s?
“Hearing somebody’s voice after 17 years even if you’re not that close to them is the most emotional thing ever. I was in floods thinking, damn my husband was right, I should have brought tissues. I had to wipe my nose on my sleeve, it wasn’t very elegant!”

Then you went on to your great, great, great grandfather Joseph Humble, who was the manager of Hartley Colliery, scene of the biggest mining disaster in England’s history, which killed 204 men and children. How was that?
“The first thing that goes through your mind is, was it his fault? That’s clearly what went through his mind as well and even though the inquest said it wasn’t, he went through hell. He was held up as a hero, which he would have hated. He was unable to cope so much he moved away to become a greengrocer. He could have been anybody’s relative, the fact that he was mine is amazing.”

Finally you looked at your maternal grandfather, Yorkshire man Stanley Carter, who died when you were 10.
“I didn’t know much about him at all, but one of my loveliest memories was the cottage he rented with big gardens and Victorian greenhouses and I remember picking tomatoes. To this day that’s my favourite smell. I knew he had been a prisoner of war, but it turned out it was in Stalag Luft III, (made famous in The Great Escape) and he was part of the escape, which was absolutely astonishing.

“A historian said, ‘without a doubt your grandfather would have been in that hut when the Germans discovered what was going on’. He wasn’t Steve McQueen, but he was the real guy.”

So what was your feeling at the end of it?
“I’ve always assumed Bill Humble was the big influence on my life, but funnily enough I’ve found I’m more like Stanley. My husband said, ‘So he was quite stroppy and refused to listen to authority?’ I didn’t think I was that bad!”