Here we go.  The time has come.  No more long training swims in the sea, reservoirs, lakes and pools.  The day has finally come for my big challenge of the year: to swim the Dart 10k.  That’s well over twice the distance of any swim race I’ve done before.  By turn I’m feeling cautiously optimistic (as they’d say in the Civil Service), apprehensive and humbled (it’s a big river and I seem to be surrounded by big fishy swimmers).

I take my time to squeeze myself into my lovely new wetsuit – big thanks to The Tri Store in Eastbourne for getting a replacement just in time.  A couple of gels tucked in, one at the leg, the other at the arm.  Lots of Body Glide round the neck (or so I thought).  A quick check for about the 26th time I’ve got everything: wristband, timer chip, inked up hand (neither can come off), Swan goggles (they’re the best), white swim hat… why do I think I’ve forgotten something?

We have our wave’s briefing that I’ve overheard twice through now, being in earshot of the yellow capped Leisurely Swimmers and the red capped Medium swimmers who have gone before and already on their way.  We are White.  This means we are Fast.  I’ll try to be but right now I’m not feeling so sure.  Behind us will be blue capped Elite.  Sharks.

Brightonian Raj Baksi, who swam yesterday, gives a thumbs up, takes some photos and tells me I’ll smash it – he has more confidence in me than I have in myself right now.  And I’ve never had a smashy aim.  Just to do it as best I can.

Off we nervously file to the entry point, over the beeping mat registering our last contact with dry land.

A careful, hesitant wade and then dive in, the water seeps into the suit and I’m underway.  Bit colder than I thought it would be but not too bad.  I can see the splashing of arms ahead – blimey they got away quick - and close up to my side.  We’re nicely spaced out, uncluttered, unlike most triathlons.  I like this rolling start.

And yes, I did the bubble-bubble-breathe thing for the first few minutes to settle into a rhythm.

I’m focusing on being at ease in the river, sensing the flow and watching my hands through the murk.  Up close I’m also noticing the swimmers around – the big rapid kick of someone to my right, nice shade of blue wetsuit to my left, passing a lady without a wetsuit who is already a deep shade of pink.  Nice new goggles mate.  A guy in front keeps lifting his head right up like a meerkat.  I pass him effortlessly, feeling smug about my crocodile eyes.

Get into your own rhythm Mike.  Stop thinking about anyone else.  I’m trying to recapture the way everything felt in synch on the long training swims: stretch, roll, tip, stretch, roll, tip.  Two beat kick.  Be long.

I’m gradually settling in to my rhythm, catching glimpses of the overhanging trees on each side of the river.  It’s breathtakingly beautiful, in a low head, sideways glimpsed way.  Occasionally a lifeguard sat on their board glides alongside while I press on – this one reminds me of a picture of Peter Pan sitting on a window ledge, silhouetted by the moon.  Curly hair, hooked nose, hunched forward as if contemplating some prank.  Come on Mike, focus!

Stretch, roll, tip.  Make every stroke count.

We’ve taken a few bends without me having much sense of where I am or how any of it relates to the explanations at briefing.  Just keep swimming.

I’ve eased passed more white caps and a few yellows and reds are now appearing, one or two doing breaststroke.  I feel a guilty pleasure overtaking fast.

More curly haired Peter Pans guiding us away from creeks and vaguely on course.

After an age, round another corner and the first feeding station comes into view – a big plastic pontoon, busy with lots of yellows and reds and a few whites clinging to the sides, grabbing at water and other stuff that I’m not going to try.  Some people are chatting away.  I realise I must be pushing hard as I’m breathing fast and deep and not able to say much more than a short “thanks”.  A quick shlurp of water and time for my first gel.  Yuk.  And I’m straight back into the rhythm.

I feel re-energised and strong.  This is awesome.

More and more red caps come into view and fade past.  Stretch, roll, tip.  Make every stroke count.  Keep pushing Mike.  Maybe some music will help – Keith Jarrett ‘On Green Dolphin Street’ strikes up.  It takes a while for me to realise there’s a kind of marine theme.  And I can’t get past the opening bars, but it seems to help keep to the rhythm.

I’m beginning to feel the wetsuit chaffing at my neck.  And my lats and triceps are starting to moan and ache about the pressure.  I tell myself “good job – at least it’s not your shoulders so you’re getting the stroke right”.  And so the shoulders start to ache too.

Come on Mike.  Keep pressing.  Keep overtaking.  Keep doing the crocodile eyes sighting.  The river has widened out and I’m getting a bit spooked and disorientated – where should I be going?  Follow the hats and the flaying arms.

Wow.  This is some way.  Make every stroke count.  Stretch, roll, tip.  Two beat kick.  At last the second feeding station comes into view and I’m alongside.  Last gel.  Sip of water.  Push off and again feeling strong and straight back into the rhythm.

Music maestro!  A doleful Boz Scaggs’ ‘Harbour Lights’ comes into mind.  Romantic but not that helpful.  ‘Times   Moves    Slow’ by Badbadnotgood: "…when you're on your own,   time     moves    slow, Running away is easy, its the swimming that's hard".  Okay, scrap the music and just look at the hands tip, pull back.  Right arm is too straight.  Think Katie Ledecky.  Back into the rhythm.

All of a sudden – smash!  I’ve swum straight into something very hard, immovable and my left hand is hurting.  Ouch.  It’s some kind of yellow metal buoy.  So much for Mr Smug Crocodile Eyes.  Bugger.

I quickly get back in to the rhythm, hoping no one has seen me, feeling chastened and a little shook up.  I’m swimming okay, back to holding the same good strong pace.

This is tiring.  Deeply tiring.  Muscles are aching with each effort.  We take another bend and there are a few waves rolling behind giving a helpful little surge.  More red and yellow caps to pass as well as a few whites.  I swim into the back of a few and try to apologise as I pass.  A few blue caps have come flying past too – first time I’ve been overtaken.  Stretch, roll tip.

I’m starting to feel like this is never ending – I can’t remember what I did before as if all I’ve ever done is this long swim.   Come on Mike, you must have had a childhood and done some other things before swimming down the endless Dart.

Round another corner and in the distance I can see throngs of people and start to hear cheering.  One last big effort.  Stretch, roll, tip.  Come on Mike.

And then it’s done.  I’ve done it.  I’m on my feet, just about standing and a little overwhelmed and emotional.  I stagger down the carpeted walkway, grinning and crying as I tell myself “I did it”.

After a little while my son and his girlfriend come ambling along the walkway – they missed my big finish but maybe just as well.  Who wants to see their dad in salty tears?

My left hand is completely bathed in blood and attracting some worried glances but I’m sure it looks worse than it really is.  After all, I can’t feel anything other than deep tiredness and achy muscles all over.  I am given a hug from one of the lovely helpers, handed a Dart 10k badge and promptly lose it, get a cup of hot chocolate and a chewy bar that’s gone in 10 seconds.  I’m finished – all spent.

Other family members are waiting, looking a little lost amongst the growing hoards of grinning, semi-dressed finishers.  I’m not sure if I should apologise for taking so long or for being so quick.

I get my hand seen to by a patient medic, who’s otherwise attending to the hypothermic non-wetsuit swimmers and pick up my bag and pre-ordered t-shirt and top.

I say “hi” to Ian Thwaites at Level Water.  There were over a hundred of us swimming for the charity and the latest is, in total, we have raised almost £40k – enough to set up new centres in twelve towns, able to teach between 80 and 100 disabled kids to swim.  How brilliant.

A bit later I find out my time and place – wow!  Did I do that?  2hrs 12mins 40secs and 2nd in my age group (though not everyone declared their age so I know that’s not really where I came but it sounds good, doesn’t it).

What an amazing experience and challenge.  And what a superbly organised, fantastic event.  I knew it would be worth it even in the times when I was training way beyond what I’d done before, getting overtired and morose.  And it certainly was.

Big big thanks to everyone who supported and encouraged me.  You’ve still time to donate to Level Water by going to my Just Giving page.  Go on.

And watch out for yellow metal buoys.