Dejected: Nick Edmondson is finding marathon training hard Jennifer Maxfield

Training for the London Marathon has taught me one very important lesson - running long distances can be significantly harder if you don't have the right gear.

I confess I was feeling quite smug having successfully plotted a 10-mile run home from work that allowed me to mix commuting with fitness and still have time for dinner.

However, I recently scuppered my plans by moving house to Surbiton - 20 miles away from my Canary Wharf office. This changed what was a difficult, but certainly manageable, jog past grumpy commuters into a three-hour epic journey with the very real risk of running out of pavement on the A3.

After a sobering glimpse at Google Maps (I had to zoom out a disconcerting amount to find my destination) I scrawled directions on the back of my hand and set off with a bottle of Lucozade and a naive smile on my face.

To say things went wrong from that point is something of an understatement.

It was during this run that I realised why there is a huge market out there for quality running equipment. People need it.

A few miles into the run and things were progressing well. I had passed through Whitechapel in east London, marvelling at the strangely all-encompassing smell of spilled lager, and crossed Tower Bridge.

Just as I allowed myself to feel a bit complacent for having plotted a route that allowed me to take in some of London's landmarks I hit a fairly major snag. My bag started to rub on my neck.

Now, as I run as a form of commuting I have come to terms with the fact that I have to carry a bag, as the necessary valuables (phone, wallet, keys, emergency Oyster card) simply won't fit comfortably in shorts pockets.

A bag strap rubbing isn't usually a problem on a short journey, but when you extrapolate any discomfort over a few miles it becomes a real problem. The strap of my small rucksack was doing its best to carve a groove in my neck at such a rate it felt like I was in a race against time to get home before it succeeded in severing my head.

Not to be outdone, my shoes and tracksuit trousers each decided to join in the rebellion and rub uncomfortably. At first it was just a mild irritant, like that person on a crowded train who puts their bag on a seat, but quickly it became unbearable.

Then the strap of my bag snapped.

Scrabbling around on the pavement outside a Chicken Cottage, picking up my possessions, each of which decided to make its escape in a separate direction from their canvas prison.

A few flawed attempts to repair the bag and somehow tie it to my person failed miserably. At one point I tried running with it crudely tied around my waist, necessitating a half run/half waddle but the look of pity and disdain I received from two runners who bounded past me like spandex-clad ninja shamed me into stopping.

I then tried stuffing everything into my pockets, leaving the bag and setting off, but I was shedding more items than the horse in Buckaroo. I realised I wasn't going to make it 20 miles.

It was while I was standing on a London Underground platform, shivering in a running vest surrounded by people wrapped up in scarves and hats, covered with friction burns and waiting for the train to take me home under a cloud of disappointment, that I decided I would have to get some better running gear.

I had learned a lesson. It's not just a case of planning a training routine, but planning the actual runs themselves. If you aren't comfortable then you're just making things harder for yourself.

Twenty-six miles is looking like a very long way.

Nick is running the marathon for Amnesty International. To sponsor him visit his fundraising page.

Nick Edmondson Trains for London's Big Run