It was a beaming Cleve West that I found at the Chelsea Flower Show at 7.45am on Tuesday, just after the announcement that the Telegraph garden had won the coveted Best in Show at the award. He had just phoned his partner Christine and his father who, he said, “was all choked up”. He had also shed a tear himself, he admitted, thinking how proud his mother, who died last year, would have been, too. For although she had seen him win two Chelsea gold medals for his previous gardens, this was the first time he had scooped the big one.

For the Telegraph, and the team at Crocus who build our gardens, Cleve’s win is triply exciting, for it has produced a tremendous hat-trick: three Best in Show awards for the Telegraph over three consecutive years. In 2009, Ulf Nordfjell took the top prize with a stylish fusion of English cottage gardening and Scandinavian minimalism. Last year, Andy Sturgeon won with a beautiful contemporary gravel garden. And now Cleve has triumphed with his atmospheric sunken garden, which plays traditional dry stone walls and modern sculptural columns against a painterly wash of flowers, herbs and parsnips from his allotment.

“I knew it was the best garden I had done at Chelsea, but you never know what the judges are going to think,” he said. For Andy Sturgeon, the result was never in doubt. “I knew he had won when I saw it the previous week. The construction was impeccable, the composition and the colours superb. Cleve is very good at leaving empty space, which scares a lot of designers. They think you need to fill a garden up. “It takes confidence to leave open areas, to let a design breathe and give you room to enjoy it,” he said.

This feeling of space has struck many visitors, including myself. The Telegraph plot seems to have a more generous width than in previous years, but it is an illusion. Instead of being directed around the garden between tall blocking features or linear axes, the eye simply floats across the low planes of stonework and planting, with only the slim columns interrupting sightlines. And the harmony is remarkable, with flowers, leaves, paint and stone continually echoing each other’s colours and patina. “Of course, I had to mention to Cleve the resemblance of his water feature to sewage outlet pipes,” chuckled Alan Titchmarsh. “He said it was bound to be me who made that connection. But no, the planting is so thoughtful. The beds are an absolute delight.”

Ulf Nordfjell also enthused about Cleve’s palette of plants, which favours species of simple, wild form and airy habit. “This is very refreshing. It gives a lightness of mood. And it is so nice not to see irises and foxgloves in a Chelsea garden for a change! The whole garden has great tranquillity.”

Three consecutive Best in Show awards speaks volumes for the unsung heroes of the Telegraph gardens’ construction team. As Ulf says, “All show gardens are a question of teamwork, and the team at Crocus are exceptional.” For Cleve, they are “the dream team – so dedicated. Everything is double-checked and backed-up like a military operation.” Mark Fane, who oversees these military operations, has been building Chelsea gardens for the past 18 years, previously for Waterers Landscapes and since 2000 for Crocus, the online plant nursery, of which he is a director, along with Peter Clay. In that time, he has notched up 18 gold medals and eight Best in Show awards – the first Best in Show award being for Christopher Bradley-Hole’s seminal Latin garden for The Daily Telegraph in 1997. “The secret is planning. We try to make every decision before we get to Chelsea,” he tells me. “And everything we can build ahead of the show, we do. “For example, this year we made Cleve’s dry stone walls in advance in sections, so on site all we had to do was piece them together. The scale of the operation is pretty vast, with probably around 50 different people involved in the garden, so we make sure everyone knows they are an important cog, what is expected of them and that jobs have to be done properly – even down to washing out the cement mixer after use, which we even had Cleve doing.”

The quality of the plants is down to Mark Straver, described by Fane as Crocus’s “plant supremo”. Some of the plants are raised in Crocus’s own nursery, and others Mark sources from different nurseries around Britain and abroad, and then brings to Crocus, so they can be potted on and watched. “Mark has a brilliant eye,” says Ulf. “And he can help give your planting an edge by suggesting new and unusual plants, as he did for me with those wonderful eremurus [the dramatic missile-shaped foxtail lilies].”

Project managing these last three Telegraph gardens for Crocus has been Peter Harket, from PH Landscaping in Devon. “He is the great organiser and enforcer,” says Andy Sturgeon. “You always feel that he is one step ahead in the build, rather than one step behind. Crocus are very good at taking all the stress away like this, even including all the form-filling, so a designer can focus just on the design.” The stress, however, does transfer to poor Peter Harket, who tells me his insomnia levels rise from about mid-April, and by the time the show opens, “I am ready for a blood transfusion.” He has regular meetings with the designer from Christmas onwards, and usually goes with him to the suppliers and craftsmen to get to know the materials. “At Chelsea, there is no crossing of fingers and hoping that something will work. Everything is carefully programmed in sequence, and we aim to finish building in a week and a half. Then I give the designer a pair of knee pads, and he has six or seven days to do the planting.” “That timing is really important,” underlines Mark Fane. “Plants need several days to settle down, turn to the light and look natural so we like to finish planting on the Friday before show week.” He said he knew this year’s design was going to be good as soon as he saw Cleve’s plant list. “It is a really interesting and unusual mix. I was a little nervous about some of the colours, but the result has turned out to be fantastic. And Cleve has been a dream to work with.”

Among his colleagues in the garden and design world, Cleve’s is certainly a very popular win. As Andrew Lawson, the garden photographer, said to me, “It really couldn’t have happened to a nicer feller.”

The London-based designer spent his early 20s trying to get into the Britain’s long jump team but in the end “my legs just weren’t long enough”. Instead he got into gardening as the best job for staying fit – and what luck he did. His ‘classic modern’ garden based on the ruins of Libya was described by the judges as a “magical experience”. The Daily Telegraph is the first sponsor in the Chelsea Flower Show’s 149 history to win the top award three years in a row after Andy Sturgeon won last year and Ulf Njordfell in 2009. Accepting the glass award, Mr West choked back tears.

The 52-year-old paid tribute to his late Anglo-Indian mother Yvette, who made her way when she first arrived in Britain playing ‘hula hula girls’ in Norman Wisdom films. She died a year ago and Mr West said he always thinks of her when the flowers are coming out as this was her favourite time of year to come down to the family allotment. He has left her a note buried in the garden.

“It’s fantastic,” he said. “I’ve worked with an amazing team and the Daily Telegraph has been great in giving me my freedom.” “My mum would would have like to have been here.” Unlike many designers, Mr West does not come from the land-owning ‘gardening aristocracy’ but has made his own way over the last 25 years. His favourite pastime is growing vegetables in his allotment below the Heathrow flight path. Indeed, the step-granddad used flowering parsnips in his winning garden – although that meant the family had to forego the vegetable in Christmas dinner.

The ‘quiet man of gardening’ is dyslexic and shies away from public speaking or appearing on television, although many have commented during this year’s coverage that he looks good on screen. Most surprisingly, in the fiercely competitive world of Chelsea, he is popular with all the other garden designers for his down to earth approach and has been tipped for a long time as a huge up-and-coming talent.

Alan Titchmarsh, Andy Sturgeon and other leading figures in the gardening world all praised his skill in bringing together historic references with modern planting. The winning garden bucked the trend for going tall this year by taking the visitor into an intimate sunken garden surrounded by warm yellow walls, flowing water and delicate trees. The three 10ft high columns with one lying on the ground, appear to be ruins but in fact mix the old and new in concrete and terracotta. However it was the jewel-like colour scheme of reds, pinks and yellows – including those parsnips – that earned Mr West a new reputation as the ‘Heston Blumenthal of gardening’ for his ability to experiment.

In the rest of the show gardens there was disappointment for old timers Robert Myers and Bunny Guinness, who were both hotly tipped. However Diarmuid Gavin’s flying garden and B&Q’s towering vegetable patch both won Gold Awards. A Korean ‘spiritual toilet’ and a garden based on wind farms won awards for the smaller gardens.

Joanna Fortnam, the Daily Telegraph’s Gardening Editor, said the winning garden stood out in a year of showing off. “There has been a lot of bling and attention-seeking, which is fantastic and people want some of that at Chelsea,” she said. “But the judges generally come down on the side of a garden that just flows, that is tranquil, that people just want to step into.”