Jeremy Guscott - here celebrating with head coach Ian McGeechan - secured victory in the Test series when his drop-goal clinched the second Test

It might just be the greatest sports documentary to ever come out of Britain.

It is certainly the most quotable, and without question the most revelatory: inside a previously hidden world, showing sport as raw and brutal and beautiful and comic, aped many times but never quite matched.

Living With Lions, the fly-on-the-kitbag story of the 1997 British and Irish Lions tour of South Africa, is 20 years old. It came to both define that epic trip, and give it an eternal youth.

Two decades on, a special BBC Radio 5 live programme has brought together the men who made it and those who became its unwitting stars.

This is the inside story of the ultimate inside story.

All good ideas start in the pub

Cameraman and director Duncan Humphries (DH): "My mate Fred and I had been making commercials about mops and buckets. We were looking for something more fun to do, so we went to the pub at midday. By 3.30pm we had this blinding idea: why not do a film about the Lions?"

Director Fred Rees (FR): "We went to tour manager Fran Cotton. He said: 'Sounds like a good idea, it'll cost you thirty grand.'

"My father and I, who ran a production company, decided we'd take the risk, because we were told by Fran and everyone else that once we had the rights then BBC or ITV would come on board and give us the money to actually make it. So we paid the £30,000, and went to the BBC and ITV, and instead they all said: 'You're mad, the Lions are never going to win, no-one's going to want to watch this film, we won't give you any money.'

"We were terrified. What do we do now? We're on the edge of a cliff. Either we've lost all this money, or we have to find a whole load more to make the film. So, in great stupidity or wisdom, we remortgaged my house."

Jim Telfer and Ian McGeechan were initially not sold on the idea of the documentary

Winger John Bentley (JB): "These two may have had a conversation with Fran, but [coaches] Ian McGeechan and Jim Telfer actually objected to their presence. They didn't want a circus. They decided to ignore these guys.

"On the first Friday, all the players went for a drink. These boys were there. They explained they wanted to do it fly-on-the-wall. I told them they wouldn't get it, and they needed a player to help them."

DH: "We all got full Lions training kit. So every day we filmed with them we were wearing the same kit as them. Straight away we started blending into the background.

"It had never been agreed that we could put microphones on Telfer and McGeechan. But we just did it, every day. And they assumed it must have been in the contract. Which it wasn't."

FR: "We lived in a limbo. We weren't the journalists, and we weren't the team. We lived in a place in between. We were ignored most of the time, which was great for the film. You don't want people conscious you are filming them."

JB: "If it's any consolation, Martin Johnson ignored all the players too."

The first game

Jason Leonard leads out the Lions against Eastern Province shortly after his epic speech

Minutes before the opening tour match, against Eastern Province, captain Jason Leonard gathered his team-mates around him in a tight circle.

His speech - set against the sound of clattering studs, nervous retching and wild exhortations ("Squeeze the arms! Squeeze!") - was Churchill meets Barking via several broken noses ("What more do you want to achieve? It's there for us…"). We nearly never knew it happened.

DH: "Before he called the lads together, Jason threw us out. So Fred and I had a conflab, and we thought, if we don't get in the first dressing room, by the time the Tests come round we won't have a chance. We had to get in there.

"So we went to see Fran. 'Fran, we shook hands on this.' 'Leave it to me.' Fran walked in, tapped Jason on the shoulder with his big hand, and that was it - we were in."

JB: "The camera had never been in a Lions dressing room. Neither had I. But we didn't even notice they were there."

FR: "There was a lot of swearing. We had one 20-second section with Keith Wood where he dropped 13 f-bombs.

"We phoned him up afterwards and told him. He said: 'Yeah, that sounds a bit much. I might have to open a supermarket or something.' So we halved the swearing, and when we played it back to him, he said: 'That really doesn't sound like me - you better put it all back in.'

JB: The phantom puker was Neil Jenkins. And sometimes Keith Wood too."

Doddie's dismay

The hand-held camera Bentley asked for was passed on to team-mate Rob Wainwright and then his fellow Scot Doddie Weir. While Weir's first attempt at self-filming did not go well ("Take two, because in part one I had a wee swear…") the next few weeks revealed just how strong a bond a Lions tour can forge - and what it's like when that bond is forcibly broken.

In the tour match against Mpumalanga, Weir's knee was wrecked by a brutal stamp at a ruck. When he was told in the dressing room by doctor James Robson that his tour was over, Humphries' camera was there to capture his reaction.

Living With Lions: Stamp ends Weir's tour

Doddie Weir (DW): "You say it breaks your heart to watch it. It broke mine too.

"I tried to look cheerful for the boys. It's the way I've always been, to show a positive side. But I was going home, and it had been a wonderful trip and a wonderful tour.

"The rugby was pretty special, yet the biggest wrench for me was leaving the 35 players. Bentos [John Bentley] was pretty special. He was my new mate. Leaving that was the biggest thing. The video picked that up, and our camaraderie."

DH: "It was close to feeling like I was intruding on private grief. Bentos and Rob and Doddie had been so brilliant and open to us, and so you'd developed more of a relationship with them.

"Witnessing Doddie - who had been playing so well on that tour - there was a moment when you wondered about turning the camera off. But you stay, and if someone says 'sod off', you sod off slightly slower.

"When I stopped filming, I said: 'Doddie, I'm really sorry.' It wasn't a nice thing to film, but it shows Doddie as the person he is."

DW: "I was a shy boy. Meeting John Bentley, who was the main social convenor, really opened my eyes."

JB: "There were some lonely days. My wife had the tour itinerary, and she would send letters and photos of the kids. My daughter was six months old when I left, and she was changing in front of my eyes. It was a big ask for me.

"After I went to see Doddie to say goodbye, I went back to my room and cried my eyes out. I didn't want to be there then. And Doddie was the nicest man in the world. I love you Doddie, I really do."

DW: "You're pretty special, Bentos. You're my favourite."

JB: "I really love you. This is a wonderful opportunity to tell everyone you love me. Tell me you love me. Please."

DW: "I'll text you."

Letting off steam

Living With Lions: Relive the famous 'court' scene

After beating Western Province, the squad retired to Cantina Tequila in Cape Town for a few beers. And then several more. With champagne. And tequila. And a lot of singing - even from Martin Johnson.

FR: "The Lions weren't holding back, so we didn't think they minded filming it. We just rocked up."

DH: "I went in the car with Jonno and Geech [Ian McGeechan]. By then we were part of the trip."

JB: "We had a great night. It finished some time on Monday. That's the real side of touring.

"People ask why Wonderwall became such a big song for us. We were in the bar that night, and it just came on. We didn't choose it. We hadn't played it in the dressing room. Rugby tours are all about singing, but that just came on and we all sang it.

"The words just worked. 'I don't believe that anybody feels the way I do, about you now…'"

DH: "We wish you'd chosen another song, because it cost us a fortune in rights to use it."

Jim Telfer's Everest

Living with Lions: Telfer's stirring Everest speech

Forwards coach Telfer was a man possessed on that tour. Convinced - correctly - the Test series would be won or lost up front, he hammered his forwards on the training pitch, then stirred their souls afterwards.

The lines have lost little of their power over the past two decades. "There are two types of rugby players boys - honest ones, and the rest…" "This is your [bleep] Everest, boys. Very few ever get a chance in rugby terms to get for the top of Everest. You have the chance today.

"They don't think [bleep] all of us. Nothing. We're here just to make up the [bleep] numbers…

"You have to find your own solace - your own drive, your ambition, your own inner strength. Because the moment's arrived for the greatest game of your [bleep] life."

DH: "We used to call Jim 'Grandad', although not to his face. He was this gentle, grey-haired man. And then he would turn up for training, and this monster would appear."

FR: "It's one of the magic things, that we managed to capture Jim and Ian making these amazing speeches. They have no ego, those two.

"It wasn't about them, and them feeling they were achieving. It was all about the players. Jim's words, and his delivery, are gold."

DH: "You would hear Jim rehearsing, all grumbling and mumbling. And then he would deliver it perfectly, and you would think, 'Where did that come from?'"

JB: "We talk about groundbreaking footage for the viewers. I'd never seen those speeches. None of the backs had. They were made to the forwards. None of the forwards had mentioned it. I watched it, and thought, 'Wow!'"

Ian McGeechan (IM): "It's the happiest I've ever seen Jim. That was him coming out. It was brilliant."

JB: "It was magical footage. You couldn't script it. That wasn't pantomime; that wasn't done for the camera. They were just lucky to have caught it."

DH: "I was a table away when I filmed it, but I don't think they even knew we were there. They were so, so focused.

"I remember the build-up to the Everest one. The sound man said: 'Jim's off on one…' He was grumbling, he was mumbling, doing the rehearsals in his own mind. I thought, 'Don't muck this zoom up.'"

McGeechan and 'the look'

John Bentley puts in a crunching tackle on Pieter Rossouw

Three hours before the second Test, with the Lions 80 minutes away from a historic series win, McGeechan sat his players down in the team hotel.

His speech would be different in tone to those of Telfer, but its impact was just as significant: "On that field sometimes today, all it will be between you is a look. No words, just a look. That will say everything. And the biggest thing it will say is 'you are special'."

JB: "That Geech speech smashes me."

FR: "There's so much heart in there. There is something very beautiful about that speech."

JB: "I was sat there crying. Crying, and scared to lift my hand to my face because of the crying.

"Because he spoke about the things that were outside the room, like your family. I missed mine so badly. I hadn't seen them for seven weeks. All of us did. Geech understood."

DH: "We had two Churchillian speakers. A few years later, the speeches on behind-the-scenes films felt too rehearsed. But there were times when I was filming when you could feel the hairs on the back of your neck rising."

The aftermath - and reaction

The 1997 Lions squad celebrate with the trophy

Tour over, series won, Fred sat down to edit the hundreds of hours of footage down to just under three hours.

DH: "The blokes who ran the four Home Unions were shocked, when they came to watch it, by all the swearing."

FR: "We played them the final sequence. When Jerry Guscott drops the winning drop-goal in the second Test, [chairman of the Lions committee] Ray Williams leapt to his feet and shouted: 'Yes!' They were OK with the swearing after that."

JB: "When we had the tour reunion, Fred and Duncan came to it. They became like friends."

FR: "The film is two hours 50 minutes long. The Lions win the Test series in the last five minutes. If they'd lost the series, it would still have been the same film.

"We knew we'd made something pretty magical. We released it as a VHS, and it quite quickly became the most successful rugby video there had been. You can never know how the world will react, but we knew we had something special."

DH: "In 2005 I was filming an advert with Jonno and Brian O'Driscoll. Brian was asked what got him into rugby. He replied that the Living With Lions film had been one of the big reasons.

"Jonno started laughing. 'This bloke made it.' Brian took my hand, shook it and said: 'Thank you very much.'"

JB: "Everyone around me said it should have been called 'Living With John Bentley'.

"I heard from the tour press officer when the film had been put together, and was told that I should have a look before it came out. So I went into the garden, and shared the news with my wife of what I'd been doing.

"She went ballistic. 'You were supposed to be playing rugby! What the hell were you doing? Why are you having to look at it?'

"A week or so later, I was away playing with Newcastle. I phoned home to see how the kids were. My wife told me a package had arrived for me.

"'Oh really?' 'Yes, it's a video from your trip to South Africa.'

"'Oh God…'

"'Well I've watched it, John, and it's just you being an idiot. As usual.'"

IM: "My wife tells me that when she's feeling depressed, Living With Lions is one of the videos she puts on. For that moment in time, it was the watershed moment. The Lions were here to stay."