A spring break to Miami that held the promise of sunshine and golf did not end in the relaxed fashion that the Duke of Marlborough would have hoped. He had planned to fly back home with his wife on April 18 to be back in Woodstock in good time for the Sir Winston Churchill Memorial Concert, which honours the memory of his illustrious godfather.

Now in its 43rd year, invited speakers at this annual tribute to the great war leader have included such notable statesmen and women as Harold Macmillan, Baroness Thatcher, President Valery Giscard d’Estaing and President Mikhail Gorbachev.

But with the duke’s flight cancelled as a result of the volcanic ash chaos, they faced an anxious wait in New York before eventually securing a Friday flight with British Airways.

“I cannot remember missing one of the memorial concerts and this year the speaker was General Sir Richard Dannatt, the former Chief of the General Staff,” the duke said, sitting in his study on Monday morning. “I just about made it. But I’m afraid that I’m still rather jet-lagged.”

Hopefully, he will be fully recovered by the weekend for another important date in his diary, when Woodstock begins 900th birthday celebrations. At 6pm on Saturday in the Town Square he will officially launch the Woodstock at 900 Festivities, when 900 biodegradable balloons will be released, whatever the volcano in Iceland manages to do.

The opening will be followed by barn dances for adults and children and a year-long programme of events ranging from Horrible Histories at the town’s carnival in June to a football tournament featuring past and present players from Woodstock and Oxford on Monday, May 31.

Woodstock 900 is the idea of mayor Peter Jay, the broadcaster and former British ambassador in Washington, who noticed that in 1110 King Henry I built a wall enclosing the park to retain his menagerie of wild and exotic animals, to effectively create a royal park.

“The wall was built to keep deer in — now it is there to keep them out,” chuckled the duke, who admits that he had not realised that such a significant anniversary was looming until hearing from the mayor.

The significance of the birthday touches him closely. What is the first park wall built in England still exists — seven miles of it running around the Blenheim estate.

For 300 years, the dry-stone wall has been demanding constant maintenance, with the task not made any easier by erosion of both stone and the number of skilled masons around capable of doing the repairs.

But the duke — known as ‘Sunny’ from his first courtesy title the Earl of Sunderland — also sees the anniversary as an opportunity to celebrate his family’s links with the town and its people.

“At various times my family have been involved in providing the town hall, the old police station, the railway station, the almshouses, the schools, the street paving, the original gas lighting and water supply,” said the duke.

“The small drinking fountain on the side of the Town Hall was a gift to the town by the seventh duke as thanks for the help of local people who helped put out the palace fire in 1861.”

Both his mother and father served as mayors and then there is his godfather, who was famously born in Blenheim.

“Sir Winston was a freeman of the borough and loved Blenheim and Woodstock. He took every opportunity to visit.”

The duke has fond personal memories of the man generally accepted to be the outstanding Briton of modern times.

“He was a great friend of my grandfather and my parents and was always nice to young people. When I was a schoolboy at Eton, I remember going on a journey with him to Manchester to inspect bomb damage. There is an old picture of me in a long overcoat that went down to my ankles. It was a time of rationing and my mother obviously thought I would grow into it.”

In 1965, he accompanied his godfather’s body on a final train journey back to Oxfordshire for burial at Bladon.

“There were lots of people standing on the platforms. But what I always remember is the sight of people just standing in fields as the train passed, with their heads bowed.”

Like his godfather, the duke’s personality was shaped by serving in the army as a young man, which he joined straight from Eton in 1944. He served in the ranks of the Life Guards in the last months of the Second World War, later serving in Germany and Egypt. Extremely shy as a boy, the army gave him a boost of self-confidence, and more than half a century after retiring from the Life Guards as a captain, there is still something of the retired military man about him.

After becoming the 11th duke in 1972 he readily admits that for many years he ran the Blenheim in the manner of a regiment with himself as commanding officer. It was not long before he was referring to the challenge of restoring and preserving his home as his own “neverending battle of Blenheim”.

Today he is supported in this task by the new duchess, Lily Mahtani, who became his fourth wife in 2008, following a service in the Private Chapel at Blenheim. His Persian-born wife, aged 52, is, he says, enjoying her new life at Blenheim.

“She has settled in very well and really enjoys living in this country. She loves my dogs and I’m very pleased that she has started to play a bit of golf.”

Gossip columnists were quick to report that the marriage has helped cement a new bond between 'Sunny' Marlborough and his once wayward heir, the Marquess of Blandford, who will one day make his home in Britain’s greatest palace.

It can now officially be counted as one of the greatest gardens, too, with the duke and his new wife last year receiving the garden of the year award from the Historic Houses Association. While planning a suitable project to mark the tercentenary of the Battle of Blenheim, the duke hit on the idea of bringing his father’s private garden back to life, which had become completely overgrown and forgotten. The work involved completely replanting it and establishing new paths and water features.

Twenty years before he had established a new hedge maze with elements of military symbolism celebrating the career of ancestor John Churchill and the victory for which this great house was his reward. The present duke may have added to the workload to the small team of gardeners but his determination to build on Blenheim’s horticultural legacy has been fully recognised.

Last year, however, one big cloud did appear on the horizon, with the duke faced with having to spend more than £1m to restore the dam at Blenheim Place, constructed in 1760 by Capability Brown. As well as forming the centrepiece of Blenheim Lake, the dam holds back the waters of the Glyme and 250 years of deterioration meant that it failed to meet the requirements of the Reservoirs Act.

“The act means that the dam must be able to hold back the water levels that would result in a one-in-1,000-year flood,” said the duke. “They have done a magnificent job but this expense has put strains on our ability to continue with other conservation and maintenance work. Some projects will have to be put back for three to five years.”

Out of the 27 World Heritage Sites in the UK, Blenheim Palace is the only one that doesn’t receive Lottery funding on the grounds that it is the only privately-owned one.

The key to survival has been to transform his family’s home into one of Europe’s greatest tourist attractions. A family seat that appeared under his father to have been almost feudal has been turned into a major commercial operation. For him the biggest change in his lifetime at Blenheim was the decision to open up the house to the public in 1950 for half a crown a head.

More than 230 people turned up on the first day with members of the Spencer-Churchill family pressed into service. A baby was dumped into the arms of the duchess by one over-eager day tripper, while the duke’s shooting friends acted as guides. Today, even the duke’s private quarters are opened to the public when he is not staying at the palace.

It had already ceased to be a family home during the war.

The duke’s memories remain vivid. “First we had 400 boys evacuated from Malvern School, then after a year we had several hundred bodies from MI5 based here. Not so secret though. You may know the old story of the conductor of the bus passing the park gates asking his charges, ‘Anyone for the Secret Service?’.”

But the duke believes that the arrival of the horse trials, game fairs, triathlons, battle proms and classic car shows have all brought in money to the local economy.

“I like to think that Woodstock has benefited. I’m sure some local people will say that they don’t want so many visitors to the town, but I’m sure that the majority recognise it has provided a sound economic base to the prosperity of the town.”

And Blenheim will, of course, be fully involved in Woodstock 900.

“One thing that pleased me is that the choir and orchestra of the Woodstock Music Society were looking for a way to contribute to the celebrations. And we were able to make available to them an original manuscript of the anthem specially composed for the funeral of the 1st duke in St Paul’s Cathedral. They performed it at their concert in Woodstock a few weeks ago.”

What will begin with balloons in May, will end at Christmas with 1,000 candles around the Christmas tree that Blenheim presents to the town.

So what would the duke’s godfather have made of the big birthday celebrations?

“I always remember a particularly telling comment that Winston once made that ‘the nation that forgets its past, has no future’. Well Woodstock is certainly not forgetting its past. Therefore it should get to have a great future.”