Q. Tell us about your childhood
A. I was the firstborn of seven children ('firstborn' sounds so much better than 'oldest'). I was the only one born inside the famous Derry Walls, in 4 Upper Magazine Street, a tenement house which was wedged between First Derry Presbyterian Church and the Apprentice Boys Memorial Hall, just below St Augustine's on the walls and Walker's Pillar (which was still standing back in those days).
I was, of course, blissfully unaware of having been placed in the world amidst so much history, surrounded by an architectural heritage of such symbolic importance, but one of my sustaining follies is that I like to think that perhaps a deep and abiding interest in old stone buildings somehow seeped into my little slumbering bones in the one-roomed attic flat that I shared with my newfangled parents.
My father was Jim Mahon, a plasterer from Deanery Street in the Brandywell area of the city, and my mother was Patsy McMenamin, a shirt factory worker who came from Bishop Street Without. That was the official name of the street and it referred to the very long and straggling portion of it that lay outside the walls. There is also a Bishop Street Within. My mother always told me that Bishop Street 'Without' meant - without indoor toilets, central heating or electric light - they relied on gas mantles in her childhood. When I was two-years-old we moved to a new house up in Creggan overlooking the old city and that's where my six siblings were born - one brother and five sisters - Anne, Kevin, Patricia, Deirdre, Pauline and Linda.
My mother was a great storyteller and she supplied me with all my early memories. She was also a talented singer with a great sense of humour and a happy disposition.
My father was a quiet, industrious man who eventually ran his own small building firm.
I spent many school holidays from my mid-teens onwards working on building sites for my father, mostly tending plasterers, mixing cement, erecting scaffolding and nailing up plasterboard.
It was tough and physically demanding work, but it gave me a deep respect for the skill and application of the tradesmen I worked alongside.
These were people who took enormous pride in the perfection of their finished work.
When I started doing Ulster Giants for the first time I realised how uninformed I might have been about the world of civil engineering. I already had a strong affinity for the nature of the work, and a genuine admiration for the dedication and painstaking precision that are the hallmarks of the profession.
Sadly, my parents' fortunes in life were to take a downward turn.
At the age of 39, my non-drinking, clean-living, otherwise fit and strong father came home one day and staggered across the room before falling into his chair.
He never walked properly again. He was diagnosed with multiple sclerosis. His physical strength and his spirit of determination meant that he became the longest-lived MS sufferer in the country, not a distinction that brought any joy to his family.
By the time he died in his 70s he had spent the last 20 years of his life unable to move any part of his body below his neck and only my mother could make out what he was trying to say.
My mother Patsy devoted the rest of her life to caring for him while still trying to raise a family of seven.
That, of course, took its toll on her and she suffered badly from depression in her later years.
Q. What are you most proud of?
A. My mother.
Q. The one regret you wish you could amend?
A. That our house at 4 Upper Magazine Street was demolished many years ago and it's now a private car park, so there's nowhere to hang a plaque commemorating my brief existence there!
Q. Do you have any phobias?
A. The sea. Well not the sea so much as being 'on' the sea for any length of time. I get truly awful seasickness. I even get 'lough-sickness' if the conditions are not flat calm. I once had to spend 10 hours with the late Olly McGilloway making a film about shark-fishing off Tory Island. The film got made okay but without any help from me. It's true what they say about seasickness - you spend the first hour afraid you're going to die and the next nine hours afraid you're not going to die.
Q. The temptation you cannot resist?
A. Mullins vanilla ice-cream with Copella apple and elderflower juice and evaporated milk poured over it. Other brands are available of course.
Q. Your number one prized possession?
A. My man bag! My wife Phil got fed up with me stuffing everything into my pockets and losing things, so she bought me a fancy leather shoulder bag and that has transformed my life. I take it everywhere with me, I carry oranges and other important stuff in it, and I don't care if people say "Get him and his man bag!".
Q. The book that has most impacted your life?
A. That's a difficult one. I read these three as a teenager and they all kept me thinking or laughing for years afterwards: At Swim Two Birds by Flann O'Brien, Catch 22 by Joseph Heller, Great Expectations by Charles Dickens (right).
If I had to do the Desert Island Discs thing and select only one then I would probably take the Flann O'Brien because it's really three books in one.
Q. If you had the power or the authority, what would you do?
A. I think I would immediately resign from the position.
Q. What makes your blood boil every time without fail?
A. Donald Trump.
Q. Who has most influenced you in life?
A. My friend Dick MacGabhann. He is my main font of knowledge and learning. From him I'm still trying to learn wisdom, patience, self-discipline, reliability and open-mindedness. I hope he doesn't read this because modesty is also one his qualities!
Q. Your top three dinner party guests, dead or alive, and why?
A. I'm most comfortable with friends at a dinner party but I understand that I'm supposed to select from the great and the good.
These people qualify on both counts. So I would choose Tom Mullarkey, architect and poet, who taught me to fish; Olly McGilloway, naturalist and broadcaster, who also taught me to fish, and Eamon Friel, songwriter and broadcaster who filled my teenage years with music.
These were all friends of mine at some stage in my life.
The many others I might choose are thankfully still alive and might be offended if they weren't in the top three.
Q. What was the best piece of advice you have ever received?
A. Don't sweat the small stuff - and it's all small stuff!
Q. The unlikely interest or hobby that you love?
A. I like to draw and paint in my spare time. I haven't done either for many years.
Q. The poem that touches your heart?
A. Postscript by Seamus Heaney. Read it and you'll see why.
Q. The happiest moment of your life?
A. My brother Kevin scoring a hat-trick against Finn Harps. He was a professional footballer and, in the opinion of many in the know, the best manager Derry City ever had.
He would say Jim McLaughlin was the best, but the club had a lot more money back in Jim's day.
Kevin had to make do with the local players available to him. Don't get me started!
Q. And the saddest moment of your life?
A. That would be to do with the death of my parents.
Q. The one event that made a difference in your life?
A. Taking part in my first, terrifying debate in the Colmcille Debating Society at the behest of my old friend Terry Phillips. It taught me how to think on my feet and the importance of preparation if you're going to be speaking in public. It was good groundwork for my subsequent career.
Q. What's the one ambition that keeps driving you onwards?
A. Simply to get better at making TV programmes. Speaking of which, did I mention the new series of Ulster Giants which is starting on Monday, July 22 on UTV, followed by a new series on Lough Erne coming up in September...
Q. What's the philosophy you live by?
A. It's an evolving philosophy which is gradually teaching me to live in the moment - which is now.
By the time I've mastered the whole thing it'll doubtless be too late.
Q. How do you want to be remembered?
A. As a very old man.
Joe Mahon presents Ulster Giants on UTV, which explores Northern Ireland's civil engineering heritage, celebrates the mighty achievements of the past that have transformed our daily living, and reveals the cutting-edge technology that will shape the future of our infrastructure. This eight-part series kicks off on Monday (July 22) at 8pm on UTV with an exploration of railway viaducts and tunnels