On Monday, October 22^nd 2012, David Walsh was sat in a Starbucks café on the M25 when he heard the news which justified the last 13 years of his career. They were thirteen years in which the Irish journalist had led the pursuit of Lance Armstrong, but this pursuit was not on a bike.

Walsh was in the vast minority who chose to look beyond the miracle story of a cancer survivor winning the Tour de France seven times, to discover and expose the truth of what the US Anti-Doping Agency (Usada) described as “the most sophisticated, professionalised and successful doping programme sport has ever seen”.

Despite the news that the International Cycling Union (UCI) had stripped the Texan cyclist of his titles and banned him for life – proving wrong all the vilification from Armstrong and his supporters – Walsh’s emotions were tempered when he found out.

The day Armstrong was told he had no place in cycling would have been the 30^th birthday of Walsh’s son, John, who was tragically killed at the age of 12 when he was knocked off his bike.

 “When parents lose a son or daughter, they seem to imagine what they would have been like at thirty. It’s a tough thing to do but it’s a nice thing in a way. The birthday means more to us than the anniversary of John’s death.

On what he felt when he heard the news, he admitted: “I was feeling hugely anti-climatic.”

Walsh’s emotions were certainly not tempered in July 1993, though, when he met a 21-year-old Lance Armstrong for the first time.

“I was full of enthusiasm. I loved the guy,” said Walsh.

“I thought ‘my god, this guy has such desire’ and I was carried along by it. I was going to be telling my mates in the pressroom that I interviewed him when he was a kid, when none of you guys knew him!”

Unfortunately, the whole dynamic changed before their second meeting eight years later. Armstrong was diagnosed with life-threatening testicular cancer in 1996, but successful surgeries and chemotherapy saw him declared cancer-free two years later, allowing him to re-enter cycling.

He was coming back into a changed sport, however, because in 1998 the Tour de France had been exposed as a drug-ridden sporting event.

As Armstrong claimed his first Tour title in 1999, sparking worldwide celebrations for this fairy tale comeback, Walsh had an uneasy feeling.

“Things happened in that race which were hugely suspicious. The race organiser, Jean-Marie Leblanc, told us three months before the race it was going to be different. There were less drugs, so we must expect slower times.

“Halfway through the ’99 Tour, we saw that Armstrong’s first title was going to be completed in record time.

“How do you take no drugs and be faster than guys who were taking strong performance-enhancing drugs the year before?”

Even more suspicious was the stark contrast of Armstrong’s amazing performance in 1999 to his four attempts at the Tour before the cancer.

“He’d never contended,” Walsh claimed.

“His best position was 36^th overall. His best position in 13 mountain stages was finishing eight minutes behind the leader. He couldn’t climb or time trial. Although he was a great rider, he wasn’t suited to the Tour de France. Anybody could tell you that.”

The day after Armstrong’s Tour victory, Walsh’s suspicions compelled him to write the following in The Sunday Times:

“There are times when it’s right to celebrate, but there other occasions when it’s equally correct to keep your hands by your side and wonder. In this case, the need for inquiry is overwhelming”.

According to Walsh, people thought the piece was a ‘terrible thing’ and the newspaper caused ‘quite a reaction’.

“I had cast accusations on a man who had come back from cancer; a saviour to lots of people,” he explained.

“The most stinging response was from a man called Keith in Glasgow, who said in a letter: ‘You have the worst kind of cancer, you have cancer of the spirit’.

“I was able to take the criticism because I had such conviction that what I was writing was true. But if I wanted to go on writing this stuff I had to get some evidence. I was never an investigative journalist, but I started talking to people and started to hear things.”

This subsequently resulted in Walsh and Armstrong meeting for the second time in April 2001. Armstrong’s agent, Bill Stapleton, had offered a face-to-face interview and Walsh – given that the interviewee was the most coveted at that time – willingly agreed, so long as they could talk about doping.

While preparing for the interview, Walsh, with help from Italian Police, discovered that Armstrong had been working with the doctor who would be regarded as the most notorious doping doctor in cycling, Michele Ferrari.

“[In the interview] I kept going after Ferrari,” Walsh said.

“Armstrong was surprised by how much I knew. Every answer he gave me was an evasion. He was furious.”

In the same year, Walsh also spoke to Steve Swart, a former teammate of Armstrong’s before the cancer, over the phone. He heard how the whole team were on a doping programme, and that Armstrong was the biggest advocate; information which was only to be used anonymously.

Walsh used all the collected information to write another piece on Armstrong, but not one he views fondly.

“I look back at that story and it’s the worst story I had ever written,” he recalls.

“I was like a 19-year-old male virgin, in that I knew what I wanted to do, I was desperate to do it, I had all the information, but I made a complete mess of it.

“It was a total embarrassment, but at least I had established the connection with Ferrari, and that made the first dent in [Armstrong’s] reputation.

“I thought it was game, set and match to me, but people had invested so much emotion into the story of Lance Armstrong they didn’t want to hear this.”

Confronted by the fact that people still refused to believe anything he would write, Walsh was searching for harder evidence before two women came to his rescue: Betsy Andreu, the wife of Armstrong’s former teammate Frankie Andreu, and Emma O’Reilly, who had been a masseuse on Armstrong’s team, U.S. Postal.

“Betsy was in the doctor’s room when she heard Lance admit to taking steroids, cortisone, EPO. Emma told me that the whole team doped, that she would collect drugs for the team, that she dumped his used syringes, that she used concealer to hide the needle marks on his arm.

“Now I had such strong information.”

With all this evidence, Walsh teamed up with French writer Pierre Ballester to write a book in 2004 called ‘LA Confidentiel – Les Secrets de Lance Armstrong’. The title was French because the book never came out in English.

“No English publisher would touch it. The French did because they’ve got proper libel laws, and if people are working honestly to bring out the truth they’re given a lot of protection.

“In this country I wouldn’t have stood a hope,” added Walsh.

Not even the book could convince people though. Such was the clout surrounding Armstrong, it actually had the opposite effect.

The journalists who Walsh was supposed to travel on the Tour with left him stranded in Liege the day before the race started in fear of being shunned by Armstrong. Fortunately, there were some French journalists who he could travel with.

Armstrong went onto win his seventh and final Tour de France title before retiring in 2005, while Walsh had spent six years unsuccessfully trying to expose him as a cheat. But he had no regrets.

“You could say he won at that moment, and could easily say I lost. But as a journalist, I feel what I did in those six years was the best work of my life. If you wanted to criticise, I would have said go to the guys who didn’t try.”

The story, however, was not finished there.

Unable to stay away from the sport, Armstrong returned in 2009, and investigations from federal agents and Usada eventually led to the UCI’s decision on that October Monday to remove the name ‘Lance Armstrong’ from cycling’s history.

Meanwhile, in a Starbucks on the M25, David Walsh’s day was about to get a lot busier than just drinking coffee.

“As soon as [UCI President] Pat McQuaid made his statement, I got seven requests from the BBC to do interviews. For 12 years I hadn’t got one call from the BBC to comment on Lance Armstrong, and suddenly I’m the man they want,” he joked.

“I called Betsy Andreu. She said: ‘I don’t even care. I knew all along’, and I felt the same.

“Then she said: ‘In a funny way, even though it would have been his birthday, it’s John’s gift to you’.”

From that moment onwards, October 22^nd would forever be special to Walsh for two reasons.