By David Owen

David Owen head and shouldersI am sitting in an Oxford hotel with Sue Benson, designer of the spectacular London 2012 equestrian cross-country course in historic Greenwich Park.

It is 51 weeks to the minute since Zara Phillips charged around the daunting 5,728-metre circuit on High Kingdom, en route to the clear round that thrilled more than 50,000 spectators and inspired the home team, who went on to take the silver medals in the three-day eventing competition, behind Germany.

Yet the emotion in Benson's voice as she discusses the day to which she devoted six years of her life is still raw; it was May 2013 before she felt able to consign the newspaper cuttings and other items that make up her personal record of the experience to a series of scrapbooks.

This is the effect that extended, full-on immersion in the Olympic bubble can have on you.

A year on, the account she gives me - via our Oxford conversation and glimpses of the diary she kept - of the build-up to the big day, paints a vivid picture of the dedication, teamwork and, at times, the mind-numbing fatigue and attendant frustrations that go into fashioning just a single piece of the grandiose Olympic Games jigsaw.

It is fitting that the hotel bar where we sit played a part in the process, since it was the venue for periodic meetings with the fence-builders - Jonathan Clissold, Scott Brickell, Andrew Hunter and Adrian Ditcham - whose brilliance and efficiency were a vital ingredient in the success of the end-product, but whose workshops were scattered around southern England and the Midlands.

Zara Phillips London 2012Zara Phillips competing at Greenwich Park during London 2012 where she was part of the British team that won an Olympic silver medal

The "beautiful" thing about this arrangement, according to Benson, is that the course, as a result, wasn't "samey: there were four such totally different skills involved; each fence had its own personality and its character because they weren't all built by one person...

"Some fences were even better than I could ever have imagined."

July 9, 2012 marked the beginning of the final, most intense, phase of Benson's career as an Olympic course designer. This was when she arrived to spend the rest of the month at Greenwich Park. Immediately, there was a hiccup.

"Refused entry into park as I had no Health and Safety hard hat and gloves," reads her diary entry. Happily, it continues: "Rescued by Jonathan [Clissold], who came to the gate with spares from the builders' compound. Not a good start."

Benson was to spend the first week of her three weeks' residence staying in this compound, near the deer park, before moving to a nearby hotel.

Though it meant sleeping in a portakabin, she appreciated the camaraderie of this experience, in contrast to the hotel, which was "more sterile and a little lonelier", albeit equipped with a bath.

In the compound, everyone ate at communal tables and benches that were "a bit like being back at school". There was a huge deep-freeze in which the builders stowed ready-made meals to last three weeks.

Everyone helped cook and some of them had brought fresh vegetables. That diary entry for July 9 concludes: "Prepared fresh beans from Andrew [Hunter]'s garden."

At this point, three weeks before competition day, the amount of rain that had fallen was a major source of concern.

Not only was there the state of the ground on the day of the competition to fret about. Much more imminently, the heavy fences would need to be manoeuvred into position without damaging what was a sensitive heritage site.

"I am devastated by the continual bad weather," reads Benson's diary entry for July 3. "I cannot sleep - so much to worry about."

It was still raining when, shortly after Benson had donned her hard hat and been whisked onto the premises, the all-important fences started to arrive, on a succession of massive, low-loading, articulated lorries.

It is worth remembering that these obstacles had never been assembled in one place before and that most of them had been viewed only in the workshops where they were built.

Sue Benson on Crescent Moon fenceCourse designer Sue Benson poses on the iconic crescent shaped fence which was the highlight of the London 2012 eventing course in Greenwich Park

"Fences look huge when they are indoors," Benson tells me. "You can't imagine them out in a big open space looking jumpable."

What a moment it must have been, then, when the first driver rolled back his container's canvas cover to reveal, for the first time in the location for which they were intended, the fences that had started to take shape five or six years earlier in Benson's mind's eye.

"For me, that was incredibly exciting," Benson says. "As the lorry driver got out and pulled open his canvas curtains there were my fences.

"Some of them were upside-down. Some of them were stacked on their end.

"The [iconic 5.4-metre-high] Moon fence was particularly difficult to unload. We really did worry we were never going to get it out. It was massive. It had to have a lorry of its own really."

The operation, moreover, had to be as carefully choreographed as a multinational corporation's just-in-time delivery system.

"The timing of each lorry coming in was critical because you couldn't have them jamming the avenue and we only had so much kit to unload everything," Benson recalls.

At one point, the schedule had to be rejigged because a truck had suffered a blow-out on its journey to East London and missed its time-slot.

Nonetheless, by July 11, after three "long but pleasing" days, every fence had been situated at its correct position on the course.

Sue Benson Greenwich ParkSue Benson was happy to help builders construct the London 2012 Olympic course she designed at Greenwich Park

"Phew. We have an Olympic course," reads the diary.

"Everyone happy. More rain."

After the high of seeing the vision she had carried around inside her head for so long take concrete form in Greenwich's much-cherished setting, a low was probably inevitable.

It duly came the next day with a vengeance, with the technical delegate (TD)'s inspection.

Benson's diary entry for July 12 reads as follows: "Today was not a good day. TD asked for new design at fence 5. This requires all six chestnut logs (the entire complex of fences) to be moved and jumping question re-designed. The trouble is the ground is at its wettest here...

"Towards the end of the inspection I am given a 30 minute lecture on the 'lack of technical questions in the last three minute sector'. I am asked if I could "find" another fence. I am told that all the competitors will gallop home, completing 'inside the optimum time', which will make it a 'non-Olympic' challenge.

"All this so late in the time schedule – TD has been living with my designs for three years - why ask for changes now?

"Nothing can be done now. I am gutted. I go into 'melt-down'. I am so TIRED."

Benson explains to me in the Oxford hotel that, with quite a wide range of abilities to be catered for and a global audience running into many millions - not all of whom would be familiar with the sport, one of her concerns had been to avoid the spectacle of exhausted horses being beamed around the planet with the potential it would bring for adverse media commentary.

"The International Equestrian Federation (FEI) asked me for a course that would test the best, but not defeat the less experienced," she says.

"With millions of viewers uneducated in the sport, I also wanted it to appeal to first-timers."

A second technical inspection was scheduled for July 23, exactly a week before the competition, in the meantime, the basic structure of the fences had to be decorated.

Here, it is worth dwelling for a moment on a presentation detail that illustrates perfectly just how much trouble is taken over every tiny element of an event such as this.

I would argue that it also shows how much time, and therefore money, is wasted on trivialities, but that may be just the jaundiced journalist in me talking.

In equestrian events, it is the norm for each fence to have a small red flag at its right-hand extreme and a small white flag to the left; the idea being that the horse and rider must pass between them.

Greenwich Park eventing cardsAgreement had to be reached between London 2012 and the the world governing body FEI over the shape and colour of the cards used at each fence on the Greenwich Park course

At some point in the wondrous journey that was London 2012, it seems, a particular cog in the machine decided it would be a good thing if the red flags were actually London 2012 magenta.

Not only that: Wouldn't it be wonderful if they could be shard-shaped, in keeping with the spirit of that marvellously edgy London 2012 logo we all had such fun with?

Of course, this all needed to go to the FEI for approval; meanwhile, Benson, steeped in the practicalities of the sport, was concerned lest the shardy flags were so sharp that they might cause injury by, for example, catching a struggling horse in the eye.

"It took about six months to agree the shape," she says, showing me an excerpt from an email that, frankly, could have been used verbatim in the much-admired Twenty Twelve BBC comedy series.

Now, for all I know, Greenwich Park was packed on July 30 with unwashed hordes lost in admiration at the brilliance of the little magenta flags adorning the fences.

To my shame, I concentrated so much on the actual competitors that I completely failed to notice them.

There was another small problem that manifested at around this time: namely that the cross-country fences in the main arena, which was being used for other equestrian events, could not simply be left in place and kept having to be moved in and out.

Furthermore, Benson and her team had to be certain they were able to position them in exactly the same place on each occasion, without having the luxury of leaving marks on the surface, as a golfer might mark her ball.

For this they used laser readings. Benson describes the arena as "a living nightmare" for them, simply because it was always in use for one thing or another.

Oh, and it was still raining. Her diary entry for July 20 reads: "40mls of rain fell in 40 minutes. My boots leak...Very tired."

Two days prior to that, she had resorted to a sleeping-pill for the one and only time.

By July 23 and the return of the technical delegate, the sun was finally shining. This seemed to signal an upswing in mood and fortunes.

"COURSE FINALLY PASSED BY TECHNICAL DELEGATE!," reads the diary, yes, in capital letters.

"No compliments but 'hey ho' - I have done my very best. Plenty of mini-alterations requested - mostly anxiety changes – all safety issues and 'what if' things...28 degrees and Jonathan feeling very ill...Late to bed - tired and dirty!"

Greenwich Park protestorsControversy over the decision to site the eventing course at Greenwich Park meant extra care had to be taken when constructing the fences

Another consequence of building a cross-country course from scratch on a heritage site was that great care had to be exercised in securing the fences.

Posts were not allowed, so the builders fell back on a brand of metal screw known as "spyrofixes".

Once again, a different approach had to be used in the main arena, This ultimately boiled down to placing bags of cement inside the fences to make them too heavy to knock over.

By July 25, when the judges came to walk the course, the temperature had climbed to 32 degrees.

"They seemed to like the course," Benson wrote in her diary. "Too tired to eat."

Barring the supervision of remaining small changes, the course designer's job was now over, so much so that she was able to attend Danny Boyle's Opening Ceremony on the night of July 27.

The last 72 hours, before US rider Boyd Martin on Otis Barbotière set out over the course, contrived to produce two further small glitches, however.

The first was the capricious weather. "We had thunderstorms on the 29th," Benson says. "This was unfortunate because we had decided to water the course for the last time that morning. The first ten to go found it slippery, after that, the ground was perfect."

Then, on measuring out the section of the course in the main arena for the last time on the evening before the cross-country, it was discovered that the distance had somehow been miscalculated.

This had to be corrected there and then, since the miscalculation actually made the course marginally shorter than the 5.7 kilometres minimum for an event of this type.

"We had to make the horses take a wider path, Benson says, something she thought she had achieved by erecting a series of Cutty Sark-shaped barriers.

Even this wasn't the end of the matter, since it was eventually decided that the designated path needed to be roped, something she had hoped to avoid on aesthetic grounds.

At every stage, of course, competitors had to be kept informed of the changes.

At last the great day arrived, and everything was...fine.

Greenwich Park eventing London 2012After all the controversy during the build-up and doubts over whether the course would be ready because of the weather, everything passed off perfectly

The weather, along with just about every other detail, was picture perfect and the complex, meticulous creation that Benson describes as "probably the first million-pound cross-country course ever produced" looked magnificent and afforded a suitably challenging test.

As befits the television age we inhabit, Benson spent the day cooped up in the control box watching screens.

"I couldn't miss anything, and the only way I could see everything was on closed circuit TV," she says.

Afterwards, there was time for a glass or two of Champagne with son and husband, a meal and a "fantastic reception" at the builders' compound.

"They present me with framed pictures of all the artist, Christine Bousfield's drawings of the final fence designs," notes the diary.

"Superb and emotional. I am sure I cried."

Greenwich Park crescent drawingAfter the completion of the event, Sue Benson was presented with a drawing of the fences, including his one, by the artist Christine Bousfield

Then, after a quick visit to the showjumping session on Tuesday morning, Benson simply caught the train home.

Her Olympics, and a six-year episode in her life, were over.

Or rather, not quite: as many have found, a job as all-consuming and emotional as helping to put on the world's biggest sports extravaganza seldom relaxes its grip so easily.

"I was very prepared for that feeling like you have just walked off the edge of a mountain," she tells me back in our Oxford hotel.

"It is a desperately low point you hit after a high like that.

"Everyone prepares for it, but still it hits you.

"For six years my every day had had something in it to do with the Olympics and suddenly it was all over."

"You do grieve because you have lost something incredibly important."

New Year's Eve, she says, was a difficult moment - "Because you think, 'It's no longer 2012. It has gone for ever.'"

Gradually, however, she has decompressed, eventually steeling herself to put together those scrapbooks.

On July 31 she and a group of those Olympic colleagues plan to picnic in Greenwich Park and walk the route that was once, so fleetingly, a stunning million-pound cross-country course.

I hope at some point on this 5.7km ramble, perhaps high up on the hill where Clissold's breathtaking Crescent Moon, with its view over Canary Wharf, was sited, I hope at some point it sinks in just how proud they all should be.

David Owen worked for 20 years for the Financial Times in the United States, Canada, France and the UK. He ended his FT career as sports editor after the 2006 World Cup and is now freelancing, including covering the 2008 Beijing Olympics, the 2010 World Cup and London 2012. To follow him on Twitter click here.