Gerald Seymour: What Scotland means to me

I'll start with a confession - get it out of the way. I have, through the family tree, links with Scotland, and the vexatious "army of occupation". My mother was a Wade, and the line goes back directly to Marshal George Wade (1673-1748), Anglo-Irish and a star of the Hanoverian military elite, who built roads and fine bridges in the Highlands. In the twilight days of the Young Pretender's rebellion, he led an army up the west coast, while the Duke of Cumberland took his army up the east side of the country and ended up on Culloden moor. Twenty years ago I started to walk Wade's roads - there were 250 miles of them - and am eternally grateful to him because the journeys have introduced me to brilliant inspirations and story themes.

I've come to love the highlands and islands, the mainland and the inner Hebrides: storylines and characters drip from the mountains and the sea lochs and the wide white sand beaches and from the wild life I watch. With my wife and Labradors I'm there each year, and without the trips my imagination would be stripped a bit naked.

For A Line in the Sand, set on the Suffolk marshes, I needed a tracker who could find an assassin - wounded and deadly - hiding out in the dense marshlands. He could only have come from an estate in the remote North-west where the red deer are stalked and shot.

He would have that particular skill of seeing the smallest footmarks in mud, the broken twig, the movement of birds that would warn of danger. He was loaned by his employer and came south on the overnight train from Fort William, and would have travelled with a mud-caked dog and in his work clothes, and would have been sneered at by career policemen - and would have done the job and found the target … and gone back on the train to the wilderness that was his home, and to the silence and the space that meant so much to him.

My friend, who stalks and guards eagles' nests from egg thieves, can sit for hours at a time, motionless and unseen, and has an affinity with his territory that is beyond my short limits of patience.

I tried to imitate, in today's Guatemala, the march of Charles Edward Stuart south from Edinburgh and as far as Derby before the start of the retreat and inevitable disaster.My failed Guatemalan revolutionary was lifted from a short and rough airstrip in an Antonov transporter of the Cuban air force. If I hadn't sat on that Scottish shore and let my thoughts churn I wouldn't have conjured my contemporary scene of flight and pursuers closing in, and time running.

I wanted, after the abject failure of a Customs team to nail the crime baron, Albert Packer, to find a man of ruthless commitment and determination and quiet leadership who would knock urgency into the hunt for evidence that would convict the big player. In The Untouchable, I reckoned such a man would come from Kilchoan. This straggling community is the most westerly on the British coast, at the extremity of the Ardnamurchan peninsula. Only the hardiest sheep survive on the slopes of the volcanic Ben Hiant, and the weaker lambs suffer from the predators above, golden and white-tailed eagles.

He's Dougie Gough, has enough probity to demand a receipt for the coffee in a polystyrene cup on the train - a second class seat - and will direct the operation that will follow Packer from London to Sarajevo, and will bring him down. Most days that I've been to Kilchoan the rain has been in the air and the winds have scarred the hills, and the beauty has been constant. Gough is one of my favourites, as is the place I've made his home.

There's a thread running through my stories of men and women fashioned by the bleakness of this corner of Great Britain. I keep returning to it because it's here that I can picture the characters of the present and the brutal burdens of history, and both can mesh together.

I write about the lonely courage of a man facing torture in an Iranian gaol, or one who is a prisoner in the cells of the East German security police, the Stasi, or an agent awaiting execution in Pretoria's hanging gaol in the apartheid days, and I can go and visit a castle ruin - Moy, built in the 14th century - and be close to the entrance to the dungeon where the sea water lapped against a rock in the centre of a prison chamber without light, without hope. The rock where the wretch would be dumped was large enough for him to sit on, but when he slept he would slip off, when he was in the water he would drown.

So many, in that hell-hole, would have struggled to stay awake, to survive exhaustion, to believe… I try to write of today's victims, but the past is an essential aid.I do it better because I have sat close at the entrance of the ruin, watched for eagles and deer, and hoped to see an otter, and allowed the forces of imagination to ride roughshod.

For The Unknown Soldier, I conjured up two torturers - former marines now running a croft overlooking a remote bay and caring lovingly for a barn full of cows, calves and sheep and goats - who would be flown down to the Home Counties to inflict pain on a terrified suspect in the hope he'd reveal where a suicide bomber would be launched. Their holding is above Ardchiavaig on the Ross of Mull and overlooking the Isle of Jura. I'm fond of the idea that men can live in remote places where nobody knows the truth of them.

On one of the Hebridean islands is a fine Georgian mansion alongside a farm house visited by Johnson and Boswell. There are days of unbroken gloom when I've been to the shore in front of the house. A grey building is set behind a grey beach that's lashed by grey seas, and above the chimneys are scudding grey clouds. The eagles aren't flying. The deer are hunkered down in shelter and the otters go hungry because the seas are too rough, even the oyster catchers and the gannets and the shelducks are missing.

It seemed the right sort of place for a British spy master, with Mossad and CIA colleagues, to induct a pair of volunteered surveillance experts - flown here by a Black Hawk helicopter - into an operation across one of the world's most dangerous frontiers. That's in A Deniable Death … and the target is an engineer whose craft is building those hideous road side bombs that kill and maim so many of our servicemen. Scanning that same house this spring and scanning the crags for eagles, I expected the helicopter to come in: when I'm in Scotland fantasy and reality meld.

Perhaps it is because a respect of this terrain and its people is in my blood that I resent leaving, and yearn to be back - and covet the ideas I'm given.

• A Deniable Death by Gerald Seymour is published this week by Hodder, priced 12.99