Stanley and I cross the finishing line at Portsmouth on 23 December (note that I came first!), where I completed my 2012 in 2012 charity challenge. The 2012th mile was passed at Mile 24, where I skipped through the seaweed and mud on the beach section and baffled the runners around me with what must have seemed like a premature celebration.

A million thanks to everyone who gave me support and encouragement (and sponsorship) throughout the year, and special thanks to the fellow runnerts who helped me through those tough last couple of months. Too many of you to mention you all but you all played a big part. Have a great Christmas, every one!

A before and after message

Before: Damn you, Caroline Williams, for getting me to sign up to this Marcothon thing. I have already run four marathons in eight days this month, with another to come on Sunday, to finish my ‘2012 in 2012’ challenge. I’m knackered and the last thing I want to do is to go out in the cold again this evening. I just want a day off running to vegetate and eat chocolate. You’ve already made me run – in the dark, in the wet, in the cold – on at least three occasions this month when I wouldn’t have done otherwise. And I’ve hated you every time I’ve had to do so!

After: Bless you, Caroline Williams, for getting me to sign up to this Marcothon thing. I have already run four marathons in eight days this month, with another to come on Sunday, to finish my ‘2012 in 2012’ challenge. I’m knackered and the last thing I wanted to do was to go out in the cold again this evening. I just wanted a day off running to vegetate and eat chocolate. You’ve already made me run – in the dark, in the wet, in the cold – on at least three occasions this month when I wouldn’t have done otherwise. And I’ve felt better every time for doing so!

The temptation to quit

The Dorset coast ultra hadf to turn into the Dorset coast marathon when I realised that there weren't going to be enough hours of daylight to see me round the final loop. I'd like to say that doing the shorter distance enabled me to take my time and enjoy the wonderful winter sunshine in one of my favourite parts of the world. I certainly took my time - so much so that even on the marathon distance I had only minutes to spare before the cut off at the final checkpoint - but my legs were so desperately tired that they couldn't have gone any faster if the entire 2012 in 2012 challenge had depended on it.

At one point, about eight or nine miles in, after the steepest cliff climb of the day, I was so tempted to follow an inland footpath sign pointing back to Lulworth that I even started unfastening the pins on my running number. I could find another race somewhere between now and the new year to make up the miles, I told myself, have a fried breakfast in a seaside caff and potter about looking for fossils while the waves lapped over the pebble beach.

The moment passed, thanks in no small part to two women who emerged onto the clifftop, gave me some cheery words of encouragement and said that I could always walk to the furthest checkpoint, get a lift back to the start and just enjoy the day. The idea of getting a lift back, short of some debilitating injury, didn't appeal at all. But they'd done enough to get my legs moving again. There were large parts of the day that I didn't enjoy at all, despite the sunshine and the scenery - I came closer to quitting on this one than any other event this year - but I made it into Lulworth as it began to get dark and so too, I'm glad to report, did the two women who kept me going when I was ready to stop.

Make-or-break time

A lazy couple of weeks (I’d love to call it tapering but I cannot tell a lie) comes to an end on Saturday with the first of five marathons in 15 days. This is make-or-break time for my ‘2012 in 2012’. I think if I can manage the Endurance Life Dorset coastal run on Saturday and I stay free of serious injury or illness I should be able to drag myself round the remaining 142 miles. I swear every mile is getting longer though ...

Day five of the Marcothon today took me from Turnpike Lane to Tufnell Park Road. Yesterday it had to be 5k on the treadmill, which almost got me disqualified as it would have been against the rules if I didn't already do some of my training runs in the gym.

Marcothon, day three

Nearly dropped out on the first weekday of the Marcothon! I got back from a school trip to the panto tired, hungry and cold and with just half an hour free before I was due to play five-a-side. I came up with 101 reasons why I couldn't possibly find the time or energy to do both. None of them were totally convincing, so I seized the half hour and went out and ran 5k - can't quite believe it but I did!

5k a day insurance policy

Here I am feeling worn out and weary, slowing down with every event and wondering where I'll find the energy to finish the 2012 in 2012. Solution? Sign up for another challenge - something called the Marcothon, which involves running every day in December for a minimum of three miles or 25 minutes.

The first two days involved no more than I'd have been doing anyway: a 5k parkrun on Saturday and Mornington Chasers winter grand prix 10k on Sunday. Along with Friday's Serpentine RC 5k in Hyde Park, these have taken me to 1,870 miles in total, so 142 still to do. Since I make the rules for my challenge, I've decided that the Marcothon can count as an event - but only if I complete it. Which means that I've still got some very big hurdles to jump in the coming week, starting with an ultra on Saturday, a 10-miler on Sunday and three marathons in the following six days. I'm treating the Marcothon as an insurance policy in case anything goes wrong with any of these.

155 to go

I had a fantasy when I started the '2012 in 2012' that by this stage of the year I would be so fit that I'd be sailing through marathons like jogs in the park. And maybe 20 years ago I would have been - maybe. Not now, old man, not now.

What I'd not reckoned on was the cumulative fatigue of relentless marathon and ultra running, more or less every week, and the effort (and at times lack of sleep) involved in travelling to and from all those various events. An unwillingness to give up other aspects of an active life (I play my 100th game of 5-a-side in 2012 this evening - sponsor me, anyone?) has also no doubt had its effect.

Anyway, November has been a hard slog running-wise. Since New York, I've done the 25-mile Six Dales Circuit in the White Peak, one of David Bayley's 'Fox@40' marathons round the lake at Milton Keynes, the Dirt half marathon along the canal at Leighton Buzzard, the LDWA'S Sundon Saunter and the Gatliff marathon in Kent. The last two were about as muddy as it gets short of swimming in a slurry tank and I found them as hard as anything I've ever done. My legs felt as tired this morning as they did earlier in the year after events of twice the distance.

I have 155 miles to do. That's one less than the Trans Britain, and I won't be carrying a pack. But I think I'm going to find these final miles far harder.