We’re following the preparations of London Marathon debutante Ellen Marshall, who grew up near Manningtree, between now and the big day on April 17. With less than a fortnight to go, panic is setting in . . .

“YOU must be excited about the marathon now,” said my friend Larry the other day, “now that it’s only a few weeks away.”

“Ha!” I laughed. “Excited? Try absolutely terrified!” Which is not an exaggeration – I am genuinely scared, which manifested itself as a huge knot in the pit of my stomach since I first looked at the official marathon route back in January and has refused to budge since.

It goes without saying that the prospect of running 26.2 miles is quite daunting. “Start to taper,” advises my training schedule. “Trust that you’ve put the miles in, and reduce your runs to a couple of half-hour jogs a week, with an hour-long run at the weekends. Don’t panic and suddenly up your training, or you may risk an injury.”

My first reaction was, fairly predictably, sheer panic, and I was finally thankful that I’ve taken the time to track each of my runs in my diary, so I have tangible proof that I have put the miles in. Last weekend I ran 21 miles, my longest run to date, and although admittedly it took me over four hours to complete and 20 minutes to climb two sets of stairs afterwards, I am now confident I will complete the marathon, even if I have to crawl those last 5.2 miles.

But what if I oversleep, miss the train and arrive late? What if I’m on time, but the trains are so full that I miss the start anyway? What if I trip over my shoelace and break my leg? What if my hip starts hurting one mile in, and I have to pull out? What if I need the loo but there’s nowhere to go? What if it’s really hot and I faint? What if I hit the wall at mile 22 and I’m sick everywhere? What if I get an upset stomach halfway round? What if I’m tired by mile 7, and just can’t go on? What if it takes me eight hours to finish?

“What if midway round a raging bull jumps over the fence, skewers you on its horns and drops you in the Thames, where you die from a combination of shock, internal bleeding and drowning?” Larry interrupted. “No-one ever got anywhere by saying ‘What if?’ Just take a deep breath and get on with it.”

Over the last few months I’ve met a lot of people who’ve run the Marathon themselves, and they all say that it’ll be the best day of my life. So maybe, just maybe, it’s time to take that deep breath, ignore the nerves and start getting excited instead.

• Ellen Marshall is raising money for Anthony Nolan. If you would like to sponsor her, please visit www.virginmoneygiving.com/ellenmarshall