But what he mainly deals in is influence.

His main job is being a landowner and he is unapologetic about that as he thinks there is a good job to be done in the role.

His efforts to make the best of it, and of the opportunities it has given him, had him made an associate of the Royal Agricultural Society this summer.

It is an honour rather than a post – an official welcome into a circle of movers and shakers. But he has been among them for some time.

He is looking forward to the Yorkshire Agricultural Society's 150th anniversary lunch for past presidents – "should be a good do". He held the post in 2002-2003.

It is part of a CV that includes negotiating for the Country Landowners Association (CLA); chairing the Oxford Farming Conference; advising the Government as a commissioner for income tax and a member of the Agricultural Lands Tribunal – until he resigned over the Hunting Act – and leading the campaign to save Farming Today, as chairman of the Rural Affairs Advisory Committee of the BBC.

He remains on good terms with the producers of The Archers and had a hand in a storyline last year involving the Country Trust, a charity which fixes farm visits for urban children – of which, inevitably, he is chairman.

Mr Henderson, 66, lives on Kelber Farm, Coniston Cold, between Gargrave and Settle, but rents the land out for grazing. His main job now, apart from his voluntary commitments, is managing the Henderson Estate, of which Kelber is a part, alongside the A65, on the border of the watershed between Aire and Ribble.

His father, William Becket Henderson, known as Becket, was one of the founders of Henderson & Feather, a Keighley mill which cleaned and combed raw wool from all over the world, shipped up the canal from Liverpool.

The profits went into land, partly because Mr Henderson senior loved hunting. A Feather family son took over the mill, now defunct, and William John Henderson, known as John, was groomed to take over the estate.

Educated at Marlborough College in Wiltshire, he then went to Cirencester College.

But he always wanted to go home and in 1976, after nine years learning his trade as a land agent in the Midlands, he returned to run the home farm and manage the estate.

By then, he was active in the CLA and interested in "share farming", an idea the CLA had brought back from Australia. Having argued in favour of it, he felt he ought to try it when one of the estate farms became vacant in 1984.

The deal was that he supplied and maintained the property and a neighbouring farmer ran a dairy business there for which they split costs and profits roughly 30-70.

It meant the landlord's take followed the fortunes of the farm but it also gave him a say in the running of the business which he said, was good for both sides – until foot and mouth in 2001.

He still says it must have arrived on the wind, to get past all the precautions they took. Within 48 hours, the whole estate was empty. But since then he has launched a couple more shared ventures.

In retrospect, he sees foot and mouth as an opportunity – compensation in the bank and time to think.

One of his tenants, David Coates of nearby Pot Haw Farm, a former point-to-point jockey, came back as a caterer to the horse-riding business – growing 'haylage', cutting it into boot-sized bales, and laying out rides of up to eight miles around the fields, with jumps, and facilities for parking and changing, for which parties pay £25 a head. (visit
cravencountryride.co.uk for details).

Mr Henderson said it was quite a complicated farming operation, because growing,cutting and moving livestock to manure the pastures have to be fitted around demand from the riders. Some of the grazing stock came from another of his share ventures, involving store cattle and sheep on another part of the estate.

It all means major headaches for the taxman and for his accountant, which is probably one reason the idea never took off.

He says it can be simpler. It doesn't have to be a landlord-tenant relationship. It is a way of mating business experience with farming experience.

But the more he talks, the more it sounds like something which works mainly because he wants it to. The contractual agreements are loose. His 'partners' – not in the legal sense, he stresses – are friends as well as tenants. It is his way of being a mentor as well as a landlord.

Mr Henderson likes part-time jobs he can juggle. From 1972 to 1991, while running his father's estate and lobbying in Westminster and Brussels for the CLA, he was a non-executive director of a small specialist steel foundry in the West Midlands – a position he was invited into through his wife Anne's family. He ended up chairing the board through to a successful sell-off in the wake of the massive restructuring which followed denationalisation of British Steel.

He likes to recount, in a lugubrious somewhere-near-Brum accent, a steelman's summary of the farmers' view of marketing: "We've produced it – some b****r better buy it."

In the past, he says, the typical farmer's reaction to lower prices was to increase production, so some farms are grossly overloaded.

He thinks farmers must "learn to believe what the figures are telling them" and drop activities which do not pay.

Five years ago, he sold the family manor, Stainton Cotes, in the heart of the estate, to fund semi-retirement. But over the years he has acquired two farms at Gargrave – he also share-farms with one of the tenants there – so he still has about 1,500 acres altogether, plus some fishing rights on the River Aire and River Wharfe, and a stake in a willow plantation in Northern Ireland.

"The value of land is only relevant when you are selling it, buying it, borrowing against it or dying." And he has no intention of cashing it in just yet.

"You need a reason to get up in the morning," he said. At 66, he still has plenty of those.

His latest enthusiasm is a campaign to stop five wind masts, close to 100 metres high, which a company called Energie Kontor wants to install on land adjoining his, in the hills which roll away towards Pendle Hill in the distance.

He stresses his sympathy with the farmers who are being offered the land rental, but he has thrown in his lot with the opposition, the Friends of Craven Landscape. He is chairman, of course.