Fernando Alonso and Mark Webber interview each other

Genuine friendships between Formula 1 drivers are rare. The competition tends to be too intense, the pressure too high, the demands on their time too great for close personal relationships to develop. And the more successful they become, the more that applies.

But occasionally one bucks the trend, and in the modern era the rapport between Ferrari'sFernando Alonso and Red Bull'sMark Webber is probably as close as any gets.

They are not best friends by any measure, but there is genuine affection and mutual esteem there, and they do sometimes spend time together away from races - as was demonstrated by the picture of the two having dinner together that Alonso posted on his Twitter account ahead of last month's Bahrain Grand Prix.

The two have been in F1 for exactly the same length of time - each celebrated their 200th race in Bahrain. They marked the occasion by getting together with BBC Sport for a dual interview - each asking questions of the other - which will be broadcast ahead of the Spanish Grand Prix this weekend.

The result was a rare and fascinating insight into their relationship, the way two top F1 drivers view each other, and the respect that can develop when world-class sportsmen compete for such a long time.

Webber and Alonso are famous for their hard but fair on-track battles, trusting their rival to such a degree that they are prepared to put their lives in each other's hands on a regular basis.

On numerous occasions in the past each has left the other just enough room - but not a centimetre more - to pull off an audacious overtaking move.

The most breathtaking example in recent years was during the 2011 Belgian Grand Prix, when Webber overtook Alonso through the daunting Eau Rouge flat-out swerves, each knowing the other would not to do anything that would put them at more risk than was necessary. Hearing them discuss it is enthralling.

"We've had some really good times on the track," Webber said.

"The one I remember," replied Alonso, "is Eau Rouge."

Webber: "There's a few guys out there - you, Jenson Button - the racing can be really hard and fair and looking a bit more at the bigger picture. There was one you were not happy with. In Bahrain in the Jaguar in 2005, I had zero grip and no traction and the Renault was completely the opposite. I was basically cutting you off everywhere, blocking you. Now I would probably get a 10-race ban."

"I don't remember," Alonso said. "It was not so bad. We met in many races."

"I've been lucky to get some moves on him," said Webber. "The one you did on Romain Grosjean at the restart in Valencia last year was an incredible passing move - very, very special move. And there was another one on me in that same race that I thought: 'Yeah, fair play.'"

Alonso: "It's good to battle with someone you respect and the battle can be fair. Some of the rookies that arrive in F1 with a GP2 mentality, it's very risky."

Webber's remarks in that exchange reveal another striking aspect of their conversation - while each clearly holds the other in very high regard, Webber does not trouble to hide the fact that he thinks Alonso is just that bit extra special.

The Australian asked Alonso what he felt his best race was, and answered the question himself before his rival had the chance to reply, picking out the Spaniard's outsanding victory at the 2005 San Marino Grand Prix, when Alonso held off Michael Schumacher's charging Ferrari in the closing laps.

In recalling the race Alonso revealed a remarkable fact - he completed the entire grand prix with a crippled engine, as a change would have meant a 10-place grid penalty.

"I had an engine problem after qualifying," he said. "They discovered one piston had a hole in it. They discussed changing the engine, which was 10 places demotion on the grid.

"In the end the Renault people decided they could do it, treat this cylinder in a different way, get the power down in that cylinder and said: 'You can finish the race better than starting 11th.' Because we were on pole. In the last laps, Michael was very quick. It was a lot of risk."

Even in recalling his own favourite race, Webber is modest enough to mention the helping hand he inadvertently received from Alonso on the way.

"Probably one of the Monaco wins - the 2010 race, I think," Webber said. "I was very fortunate that you crashed in practice there, which helped me a bit, because you were quick all weekend, along with Robert Kubica and Seb Vettel.

"It was the four of us going for the win. Robert was very quick on the prime tyre but I got myself in a good position in qualifying - both laps were good enough for pole. The race was…"

"Control," Alonso interrupted.

"Yeah, I could manipulate the gap quite easily. Yours?"

"I think it was Malaysia 2012. It was completely unexpected. I started ninth and then the red flag stopping the race. When you stop for an hour and a half it's really challenging for the drivers, to see how the grip has changed. The car felt good, I felt good that day, starting on extreme wet tyres then inters and dry. Very challenging."

The conversation moved on to their biggest accidents in F1, and inevitably they brought up Brazil 2003, when in damp conditions Webber lost control of his Jaguar while flat out coming up the hill towards the pits. Alonso ploughed into the wreckage and needed medical attention.

"I was on heavy fuel on inters trying to go to the end of the race," Webber recalled. "Going up the hill, I made the really bad mistake of going on to the wet part of the track to cool the tyres. I didn't realise how slick the tyres were. Gone. In the wall. Fernando was being encouraged by his team to pit quite quickly. People don't understand how steep it is."

"Blind," Alonso agreed.

"And you had a huge shunt. We stopped the race together," Webber said. "Your biggest crash in F1?"

"Yeah without any doubt," Alonso replied. "You?"

"I think Valencia (2010, when his Red Bull flipped after hitting the back of Heikki Kovalainen's Lotus). It was spectacular and also the hit into the wall was more impressive. I snapped the brake pedal in half with the adrenaline or the pressure or whatever. The pedal shouldn't snap. But the force of going into the wall and what I used broke it."

"Me too in Brazil," Alonso said. "Both pedals."

Alonso then asked Webber which was worse - his flip in Valencia or the two he experienced in a Mercedes sportscar at Le Mans in 1999?

Webber has previously said that when his car took off for the second time at Le Mans he felt he was unlikely to survive, so his reply to Alonso's question is revealing.

"Probably F1," he said, "because more people are watching, especially my mum. In Le Mans, no-one was watching. If I get my helicopter licence you can come with me."

"No way," Alonso laughed.

But perhaps the most revealing answer of all was Alonso's reaction to being asked whether their relationship had changed as a result of all the pressure in F1.

He said not - even when both were involved in one of F1's greatest ever championship fights, a five-way tussle involving themselves, Vettel and McLaren drivers Lewis Hamilton and Button.

Alonso said: "I wanted to win; second choice was Mark. Nothing changed in our relationship. It was even better, I think. I think at the end we were even closer than at the beginning."

See more of Fernando Alonso and Mark Webber's memories in the build-up to the Spanish Grand Prix starting on BBC One at 1210 BST.