Almost four days to the stopwatched second since she ran wearily, wondrously, into Lands End, Sharon Gayter almost bounces to the door of her home in Guisborough, Cleveland. It’s Tuesday evening.

The new world record holder, the first woman in history to footslog from John o’ Groats in under 300 sleep-starved hours, is bright, beaming, buoyant. She has caught the sun, perhaps because there was little chance the sun could catch her; she has lost around 8lbs from an already spare frame but that’s a bit of guesswork because her feet are too masticated firmly to plant onto the scales.

Het story had made a two-minute slot on ITN, attracted more than a million hits in 24 hours on the BBC website, made the front page of the World Service. She at the top, then Trump,

She is 55 and a chronic asthmatic, represented England for 18 years, broke the Lands End-John o’ Groats record in 2006, holds many others, drives ultra to almost impossible extremes.

Easy to ask why, harder to elicit a reply that doesn’t honestly imply “Why not?”

Her husband Bill, the greatest support party since Tensing joined Hillary, comes down a minute or two later. He’s a lorry driver, back at work at five o’clock on Monday morning, has done a couple of Scunthorpes (as he puts it) that day.

Like his wife, he appears in remarkable good fettle, though not immune to her taunts about his pasta cooking along the 822-mile odyssey.

“She’s like Goldilocks. Always too hot or too cold, never just right,” says Bill.

“He makes a good beans and sausages, though,” says Sharon.

Baxter, their rescue dog – apparently named after Jim Baxter, a footballer of some renown – appears delighted to see them both but may be little help in addressing the 1,500 emails which await Sharon’s triumphant return.

Increasingly, incredulously, an internet audience had tracked her pained progress step by step, save for when technological malfunction mixed up Wigan with Abergavenny.

Easy mistake, anyone could make it.

Then there was the time the GPS led her through someone’s back garden. “I was a bit worried when I got to the greenhouse,” says Sharon.

“I nearly pinched some tomatoes,” says Bill.

At Lands End, journey’s end, Facebook flooded. Spotting the finger post to New York, someone wondered if she might just carry on.

“Any chance of a lap of honour?” added a second.

“I bet she does a Parkrun on Saturday,” wrote a third.

Prophetic? This very Saturday, 9am, she’ll be under orders for the 5k Parkrun around Catterick racecourse.

“You have to stay fit,” says Sharon.

She’d reached Cornwall’s westernmost extreme at 6.35 (and a few seconds) last Friday evening, fortified by a Big Mac and chips 20 miles from the finish – “I had to run across dual carriageways to get that,” pleads the pasta cook – but was stopped on the A30 towards Penzance by police who didn’t like her running along a busy road.

They asked if it were illegal, were told it wasn’t, wondered how else they might make Lands End. “They let us off with a warning,” says Sharon.

She insists that she wasn’t emotional that evening, has never seemed the emotional type. “I thought that I might be, but maybe it was because it was daylight and all those people around.

“All I wanted to do was sit down and then have my first shower for nine days. The support party wanted to watch the sunset but I just went to bed in my stinky clothes and fell asleep immediately.”

For the 12 nights previously she’d averaged less than four hours in the back of a cramped camper van.

And Bill, he who had cycled, supported, stressed, perished the pasta and (time and again) forgotten the ten grapes with her 5am yogurt? “I was very proud but I think mainly just relieved it was over,” he says. “The stress was horrendous, especially when we couldn’t work out where she was. I saw how much she was suffering.”

Though most meals were taken on the hoof, she preferred still to drink from a proper cup. “Someone gave me one something about ‘mad woman’ on the side,” says Sharon. “I can’t think what they meant.”

They are an extraordinarily close couple – symbiotic, some might say – met on the buses after Bill left the army and she moved to Cleveland from Suffolk.

He’d meant to propose over a romantic Valentine’s Day meal, bottled it, asked her the following evening after fish and chips from the paper. They were married three weeks later in 1992 at Gretna Green, regulation witnesses roped in from the street.

Sharon’s now a lecturer at Teesside University business school, became a permanent staff member on Monday after years of zero-hours contracts and because of a breakfast radio interview was two minutes late for the induction session.

“A few people looked until they realised,” she says. “We had to watch a video. No offence, but I nearly fell asleep.”

She’d finally had a shower on Saturday morning – “an hour to hobble to the block, just a T-shirt and a towel” – discovered the van wouldn’t start, sorted a two rope, broke it and finally reached Guisborough at 1.30 on Sunday morning.

By breakfast time she’d posted images of piles of washing, a little later of Bill – good old Bill – doing the shopping.

When we meet, she still hasn’t answered any of the emails but discovered that on the back of all the publicity she’s sold 17 more copies of her autobiography.

A second book, about the latest epic, will follow. A third – “more technical, not just a lot of stories” – will examine the scientific side of ultra running and form part of her PhD thesis at the university.

End of the road? Though she’s promised Bill never again to pound the length of the country, this one could run and run.

Her time sought, she’d offered to make the 100-mile round trip to come to us, then offered to make dinner. Instead we repair to a pub near Guisborough where she eats pretty well but drinks just a solitary orange juice.

Despite the publicity, none recognises her – or, at least, affects to. “I’m not a celebrity, I don’t want to be,” she says quietly.

Though she insists that giving up was never an option – “it’s not like a marathon, where you can try again in a few months” – the darkest hour, physically and emotionally, came late one night when she seemed simply to collapse in the road.

Bill had summoned from the day’s intended finishing point. “She was slurring like she was drunk,” he recalls. “We tried to get her going but she didn’t make 50 metres. They asked me what to do and I asked them why they were asking me. After a few hours sleep she was back on the road.”

“Not so much collapsed, just in need of a good sleep,” she says. “If you’ve run 500 miles, you’re not going to pack up with just 300 to do.”

On another occasion she became lost amid a house construction site and, finally oriented, discovered that a bridge was closed. “I think I just lay in the road and shouted,” she says.

No swearing? “She doesn’t swear,” says Bill. “You just get the look. It shrivels you.”

In truth it proved an obstacle course – record heat, knee-high floods, unscheduled road closures – all surmounted with the help of a support party which as well as Bill comprised Trevor and Linda McDermott, the Catterick Parkrun organisers, retired police officer Izzy Wilkinson and Eleanor Robinson, herself a former record breaking long distance athlete.

“They were brilliant,” says Sharon. “Trevor’s so meticulous, but always knew how to make you laugh just when you needed to.”

Her body’s become anaemic, some nerve ends in her feet are gone, a few other reminders remain. “I’ll be fine in two weeks,” she insists.

So what next? One possibility’s a crack at a 500-miler around Scotland’s northern extremities – she thinks she can break the men’s record for that – another a million metres, around 620 miles, on a treadmill back at the university.

Bill’s part pragmatic, part philosophical, supportive ever more. “Just as long,” he says over a pint of the stuff that refreshes the parts others can’t, “that she never again tries to run from John o’ Groats to Lands End.”