I had a real defining moment today. My parents and I went out for a walk around the Prime Minister's country residence of Chequers south of Aylesbury. It was a wonderful walk, full of twists, turns, ups, downs, hills, valleys, woods and open landscapes.

After six miles we stopped for lunch on the side of a valley looking down to the bottom and across to the hills on the other side; the whole view was encircled by green and orange trees ready to drop their leaves for a stiff breeze. A beef and pickle sandwich and a slug of sloe gin steeled us for the final mile of hilly terrain. As we set off the gentle drips of rain that accompanied our lunch turned into a heavy shower so I donned my waterproof jacket and set off. We went down to the valley floor, steadily up to a peak, round the side of one hill and approached the steep side of another: Beacon Hill at Ellesborough.

I'd said during lunch that I was looking for a hill that would challenge me. I wouldn't say as much to my parents but the ascents we were attempting weren't challenging me at all, and sticking to their pace - particularly my mum's, bless her - wasn't really pushing me as much as I'd like. I've felt for a while that I'd rather push like mad to get to the top and push my body hard than pace myself and not tire myself out.

So it was that I stood facing this hill with apprehension but almost certainty that I'd get to the top without stopping or collapsing. As mum and dad started steadily up the side I prepared myself by shedding my waterproof layer and rolling my sleeves up. I grabbed my walking pole, tightened my pack straps and started on my way.

After the first third of the climb, I could feel my heart pumping in my chest and my breathing was picking up. I passed my parents taking a breather half-way up and resisted the urge to look at the view they alluded to. As I kept pushing I felt twinges in my legs and feet that had announced themselves at various times through the day but they soon disappeared when the summit came into view. I was wondering how much further to go when a peak appeared and gave me something to aim for. I hadn't slowed my pace except for tough parts of terrain and on reaching the top, panting like a dog, sweating somewhat and feeling my pulse in my entire body, the sun was out and I took a look around me.

What a view! I'm not sure there are words to describe the combination of adrenaline, pride of achievement and the astounding vista which greeted me as I caught by breath at 225m elevation. I was so very pleased with myself for tackling such a hill and proving to myself that I'm capable of such things. I can definitely see how climbing up things and looking down can become addictive because I got a real natural high at the top of that hill.

My only regret is that my mum seemed eager to get on our way, so we only spent a couple of minutes at the top before descending 75m back to the car. Next time, I'll be staying for at least fifteen minutes to take everything in.

Photos to follow, hopefully.