It was only a stroll.

A quick walk a few miles along the coast. But Bill Taylor's Sunday afternoon wander in Easter Ross probably took him into Caledonian immortality. Nobody can be sure. However, it may well be that his outing to the north-east of the wonderfully named village Hilton of Cadboll – accompanied by 30 family and friends – meant Taylor had visited more bits of Scotland than any other person in the land. More than kings and queens, warriors, poets or pilgrims.

He has travelled from the northern shore of the island of Unst in Shetland to Southend on the tip of the Mull of Kintyre, and from St Kilda in the west to Peterhead Bay in the east - but crucially he has been to all the bits in between as well.

He almost ran over a corncrake on a bike on Tiree – "I was on the bike, not the bird" – and found his forbears in a Borders graveyard at Kirk Yethholm, and in a cemetery on the Mull of Kintyre.

It was all part of a rather eccentric challenge – "it wasn't a mission, just a daft idea" – he set himself more than 20 years ago after a conversation with a friend called Paddy Deasy, who was obsessed with hillwalking.

Taylor, who recently turned 60, says: "Paddy had climbed all the Munros [mountains over 3000ft] and had just finished the Corbetts [those between 2500-3000ft] but he had never been to Orkney or Shetland. I thought, 'Hey, I've seen more of Scotland than him.' Then I asked myself, 'How would you be able to say you've been all over Scotland?' It was just an idea that started to grow in my mind."

He quickly realised he would need a grid, and recalled the quarter-inch map of Scotland that used to cover a wall in the flat he shared as a student. This divided Scotland into 10km squares. There was no template to follow for his project so Taylor, from the Black Isle, dug out some old Ordnance Survey maps and set about making up his own rules.

"There was the question of whether I should go to the likes of remote, uninhabited islands such as Sula Sgeir, North Rona or Rockall. So I said no, let's be realistic. Let's work on the basis that I go to those which are occupied, or physically attached to occupied squares. That of course raised the issue of tidal attachment. I decided they had to be attached at high water spring tides – not tidal. So if there was a rock offshore which is in a new 10km square, but isn't attached, it wouldn't count."

Taylor, a geographer, conservationist and heritage tourism expert, defined being occupied as having at least one person living there on the electoral roll – giving him 1080 squares in total to visit. Flying over a square wouldn't count, and neither would sailing through one. "I decided I would have to make some kind of physical contact with the ground. I would have to drive or cycle through it or take a train or a bus. The ones that aren't on the roads or the rail required the greatest effort."

On one occasion that effort involved him persuading the skipper of a boat to sail close into the shore on the west of Skye.

"I realised the cliff opposite was in a square I hadn't been to, so sat on the bow of the rib [rigid inflatable boat] and got the skipper to ease the boat in so I could put my feet on to the bottom of the cliff on the north side of Loch Brittle, and tick off another square."

Most of the squares, away from the transport network, have involved a great deal of walking.

"I never resorted to using GPS," Taylor says. "I would take a map with me, and pick a physical feature within that 10km square and go there – perhaps a wee loch or where two burns meet. There are some in the Flow country of Caithness and Sutherland that you are not 100% sure you are in, because there are few if any features – miles and miles of bugger all. So I would go an extra 100 metres to make sure."

There were other squares that utterly captivated him. "The Shetland island of Foula just blew my socks off. It is an astonishing place. There are only about 25 people on the island. Their airstrip, which I think they helped build, is like a postage stamp, torn in half. Half of it goes up a hill, the other comes down.

"I was up front with the pilot and he was talking to people on the ground who said there was sheep on the runway, so we just went round again." He felt that nicely symbolised the island community's relationship with the outside world.

"Foula to me had even greater sense of remoteness than St Kilda, because it still has a real community living there beside its extraordinary physical features. The cliffs on the west coast are just staggering. There is a glacial valley cut right through them and when you look one way there is a 1000ft drop straight down, the other way is 800ft straight down. It is all on a massive scale but people still live and work there. It is a great survival story."

Then there was Gloup, in a remote corner of the Shetland island of Yell. Taylor had heard about it many years before, from a Shetlander training for the ministry in Aberdeen. A gloup is a blowhole in the cliffs that takes in sea water and spits it out again.

"I always thought the name wonderful, almost onomatopoeic. You could just hear the water 'glouping' in from the sea. I never thought I would get there but I never forgot the name."

Gloup almost caused him a major setback. "I was trying to do 16 squares in six days on Shetland. It meant going to Foula, Fair Isle, Out Skerries, Muckle Roe, Yell, North Roe, and I had to fit them all in using planes and ferries in April's northerly gales. I was managing to do it, but Gloup was the second-last square and I was running late. I had to get back on the ferry to Shetland mainland to make the connection to Out Skerries before getting the flight back to the Scottish mainland. If I didn't do that I would have had to make a special trip back to Shetland, with all the time and expense. So I was running for quite a bit, and was wrestling with my conscience as to whether I could just lie about having been there. But then I realised if I just went up a hill I would get into the square without following a long, laborious path. I did a wee dance in the heather when I got there on time."

But it wasn't just the far-flung island locations that made an impression.

"A real surprise was in Ayrshire. Just south of New Cumnock is Afton Water that Burns wrote about. I suspect very few have been there unless they are from Ayrshire, but it was an absolutely beautiful little valley, glorious. Driving through New Cumnock, you little expect there is such a gem so close."

He was glad to explore the Borders as the paternal side of his family can be traced back to Kirk Yetholm. "There is some lovely country there, the steep wee valleys on the flanks of the Cheviots. Good Borders sheep country, where there is different way of life," he says. Other family connections on his maternal side took him to Southend on Kintyre.

Taylor thinks the seeds of his epic journey were first sown when, as a boy, he would pore over his father's 1895 Bartholomew's Atlas Of Scotland. "It was monster and I used to love studying the place names, and trying to imagine what they would be like."

He was born in Uddingston in South Lanarkshire but at the age of five moved to Bothwell. His mother's family were from the island of Colonsay and he used to go on holiday there, which helped develop his love of islands. "I remember it very fondly, going to remote beaches and headlands. The ferry Lochiel used to go from West Loch Tarbert, and be met by flit boat [which took passengers to and from larger ferries] off Colonsay. I remember being handed down from the ferry by a big MacBrayne's deck-hand and thinking this was cool."

At 18 he went to Aberdeen University to study geography, then a master's degree in rural planning. While a student, he got into hillwalking, visiting may parts of Scotland he had first glimpsed on his father's ancient map. It was a pattern that was to be maintained throughout his student and working life. It meant he could tick off many of the 10km squares at the start of his project 20 years ago.

In 1979, after graduating, he got a job with the old Nature Conservancy Council on Rum as the summer warden.

"It was when I was there I actually got to one of the most obscure squares right on the most westerly point of Rum," he says.

He then got a job in East Kilbride as the first countryside ranger for Calderglen country park.

By 1988 he was warden at Beinn Eighe in Ross-shire, then Scottish Natural Heritage area officer for Wester Ross, after which he moved to the Black Isle with his family.

In 1998 he won a scholarship to go to Australia to look at wildlife tourism in World Heritage Areas, and later became Highlands and Islands Enterprise heritage manager. He now works as a heritage tourism consultant, which allowed him time to panic the week before last because he realised he had missed one square in Lewis and one in Ayrshire. After doing them, it was that walk in Easter Ross that meant he met the target his sister had set him of doing them all before his 60th birthday.

So what are his reflections on decades spent ticking off squares on the map of Scotland? "I largely went by public transport and most of it was on time and comfortable," he says. "Some of it was great value. On Orkney I flew from Kirkwall to Westray, then the shortest flight to Papa Westray, spent a few hours there, then out to North Ronaldsay and back to Kirkwall, all for £36. That to me is astonishing value.

"The thing that continues to amaze me is the incredible diversity of Scotland. I used to do presentations for overseas visitors and I would say to them that if you start in Inverness and you go 100km along the eight main points of the compass you will arrive in places that are geologically, climatically, architecturally, linguistically and ecologically different. You can do that across a lot of Scotland. Just follow the compass and you will experience a diversity I don't think another country of our size can equal. The more I travel the country, the more I am in love with it. I have no doubts at all that it can hold its head up in the world.

"Generally I found everybody and everywhere welcoming. The Scots love visitors but can be a bit ambivalent about tourists. The only access difficulties I encountered were at Eishken Estate in the south-east of Lewis."

So is there a book in this for him? "I don't know, but it would be good to get other people to start looking at a map of Scotland, and just sometimes get off the main routes to find the gems that Scotland has to offer.

"And there are still a couple of places I want to visit. Strangely enough I have never been to the island of Raasay, for example, as I went to another part of its square."

But before that, Taylor has to get back to his local, the Anderson in Fortrose, where the Cromarty Brewery has left a keg of special beer – The 10 Square Chappie, a wee bit of acclaim for a man with a wonderfully daft idea. Oh yes, and Paddy will be there to sample it. n

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