Like Olympic star Helen Glover, Julie Summers only took up rowing four years ago.

But while Ms Glover is now busily showing off the gold medal she won in the women’s pairs at Eton Dorney with Heather Stanning, Ms Summers last weekend was taking to the water at the Oxford City Royal Regatta.

Yet both these two tall and ferociously determined ladies are, in their very different ways, remarkably late arrivals to the sport.

For while Oxford historian Ms Summers does not exactly have the Rio Olympics in her sights, by making rowing her passion at the age of 51 she has shown it is never too late to begin racing on the water.

Not only that — after writing numerous books on subjects ranging from the Second World War, to Everest and the Shackleton voyages — she has recently produced Rowing In Britain, a new history of rowing as a competitive sport from the early 19th century to the present day.

Ms Summers, of Iffley, sculls for Oxford’s Falcon Rowing Club under her married name, Steele.

In May she and her crew won gold and silver at the British Rowing Masters Championships at Nottingham.

The Oxford City Royal Regatta on Saturday saw her, for only the second time, competing with her 21-year-old son Simon, who has been rowing since the age of 12, with roles well and truly reversed once they step off the riverbank.

“He is completely in control. I do exactly what I’m told. I feel real pressure to perform,” she laughs.

But while she has spent hundreds of hours cheering on Simon, who rowed for Wallingford and GB as a junior, and her younger son Richard, 19, now captain of boats at Christ’s College, Cambridge, she insists that the inspiration to take up rowing at 47 came from elsewhere — strangely, from the slopes of Mount Everest.

Ms Summers is the grand-niece of the 22-year-old Oxford University student Sandy Irvine, who perished on Everest in 1924 on the famed tragic expedition with George Mallory.

She wrote a biography of Irvine, fuelling new interest in one of climbing’s greatest mystery — did the pair last seen just 800ft below the summit actually make it to the top before meeting their deaths?

And while researching the life of her famous great-uncle, Fearless on Everest, she learnt what an outstanding oarsman Irvine had been at Oxford, rowing in the Oxford and Cambridge Boat Race in 1922 and 1923.

“The invitation to join the Mount Everest expedition was issued on the strength not of his climbing skills — which were largely untried — but because of his abilities as an athlete,” said Ms Summers.

“Sandy had rowed at Henley for Shrewsbury School and later Merton College, Oxford. When I wrote the book I had to do some serious research into rowing as I was not an oarswoman myself.”

The final push into the boat came from her elder son.

“Simon told me one day, ‘if you want to really understand about rowing and competing, you have to get into the boat’. So I took up sculling.”

At the beginning of the year she was approached to write a history of rowing to coincide with the London Olympics, which involved an unexpected race against time.

“When the senior editor at Shire Publications rang me to ask whether I could write a book about the history of rowing in time for the Olympics I thought he might be joking or thinking about 2016.

“But, no, the book was to be a 10,000-word potted history of rowing with 70 photographs and the deadline was less than a month. I agreed. My friends thought I was mad.

“I was helped by a Shrewsbury School old boy and two-time winner of Henley’s Princess Elizabeth Cup, Richard Owen.

“He had invited me to the Henley Regatta in 1999 to learn the basics. We hired a rowing boat and moored on the booms opposite the Stewards’ Enclosure.

“He explained everything he could think of and answered all my questions about the progress board, the distances and the history of the events“ Then, as a boat passed by, he made an unusual request.

She recalls: “He said, ‘lie down and put your head as close to the booms as you can and listen, feel the power of those eights, feel the wind against your face, listen to the clunk and the swish of the blades’. I did. It was absolutely thrilling.”

She said Rowing in Britain (Shire. £6.99) is designed to give a very brief history of the sport to people who know little or nothing about it, who watch the Boat Race every year and became armchair experts during the Olympics.

“What I have tried to do is to depict the essence of rowing — its highs and lows, the visceral excitement of a Henley win, the discomfort of cold mornings on the Tyne, and the vicissitudes of the Boat Race — and bring them to the fore.

“As I researched I came to realise just how wide is the reach of rowing in Britain. Rowers were responsible for codifying many of the sports that developed in the 19th century. Nutrition was already being discussed in Oxford 150 years ago.”

But it was the elite mixed doubles sculls at the Oxford City Royal Regatta that was at the very front of her mind. Competing with her son would be special.

“Rowing with a man is just so much more powerful. It is a bit like driving a car with the engine of a Rolls-Royce rather than a Mini.”