Gavin Hastings says the tension was palpable, adrenaline surged through his veins and he felt as if his heart was trying to burst free from his chest.

The occasion was the final Lions Test against New Zealand in 2017 and Owen Farrell had just kicked a penalty from downtown to level the scores at 15-15. Hastings, a former Lions captain, was merely a spectator inside Eden Park that day but his insides were going haywire - that's how febrile the atmosphere was.

Then came the real theatre, a twist in the tale that will live long in the memories of all who witnessed it: as the All Blacks roared back seeking a series-clinching score Lions hooker Ken Owens was adjudged to have been offside from the kick-off and referee Romain Poitre signalled for a kickable penalty to New Zealand, then overturned it after consultation with the TMO.

Amid the frenzy and tumult of those final seconds of that thriller in Auckland – with 30,000 supporters roaring the Lions on – Hastings says he was struck by something unmistakeable: the calm authority and the aura of leadership in the face of adversity exuded by Warburton as he and his opposite number Kieran Read were called together by the French official.

“Sam Warburton is calling for calm as the referee raises his arm and for me this is just great leadership – doing the right thing at the right time. He goes up to the referee and says 'you have to check' and he didn't know what he was asking the referee to check for; he just thought 'if we can calm down here rather than the penalty being awarded well, what's the worst that can happen?' It was the manner in which he approached the referee that got the decision reduced from a penalty to a scrum.”

It was certainly impressive stuff from Warburton in the red heat of battle, an environment Hastings – veteran of two Lions tours - knows all too well.

“Lions test match rugby, playing a Test series against the host nation is just one of the great sporting things when you have got 30,000 Lions supporters just absolutely 100 per cent behind the team. It is evocative. It is what the Lions are all about, it is what the Lions has become. It's the only time I ever wished I could pull on a rugby jersey again. It's bigger than a World Cup final almost, or certainly the equivalent of a World Cup final, when it comes down to that [a deciding Test]. It's just massive sporting theatre and unlike theatre you don't know how it is going to end.”

It is evident that Hastings remains in thrall to the whole Lions experience, so much so that he has co-written a book with rugby author Peter Burns on the subject. Legacy of the Lions is not just about his time in a Lions jersey but also details those teams that came after the sides he played in through the prism of the main protagonists: Warburton, his predecessors, the management, Ian McGeechan et al.

It is an homage to leadership and the unique challenges faced by those in charge of a disparate group of individuals in a fleeting moment in time and how even the smallest decisions taken can influence the outcome of an entire Test series and thus the pictures behind the victories over Australia in 1989 and 2013 and South Africa in 1997 are coated with fresh paint while the curtain is pulled back on the defeats against the All Blacks in 1993 when Hastings was captain and the whitewash of 2005, when Clive Woodward selected 45 players and three captains, and the loss to South Africa in 2009. It makes for a compelling read.

“The whole essence of doing this book was that I was fascinated about the differences between the successful tours and the tours that weren't quite successful and with the obvious exception of 2005 every Lions tour since 1989, they have won at least one Test match out of three. That in itself is an incredible achievement when you think that the guys have just come together a few short weeks before and moulded themselves into a team that is capable of beating in many cases the current world champions and to get even one victory out of three is a hell of an achievement,” says Hastings.

“The squad will never be the same squad again. They go on to a new challenge in a new country. There are a hell of a lot of games that are remarkably close. The obvious exception is 2005. Clive Woodward tried something different with his squad of 45 players and in many respects looking at that I'm glad it didn't work because if taking 45 players away for 10 weeks was going to prove to be the recipe for success, it was a huge resource, and the Lions doesn't need that. It wasn't right for the Lions. You learn more from your mistakes than from not making them, the mistake would then be to make the same mistake again. Learn from them and move on.”

Hastings was, of course, named captain of the Lions party that lost 2-1 to New Zealand in 1993. It was a side picked after plenty of horse trading between representatives of the home nations and had an impact on certain players who found it difficult to motivate themselves for the midweek side.

“The selection of that squad was done very much by a negotiation process by selectors who were trying to argue the case for having people from their country there which seems to be an anomaly,” says Hastings. “New Zealand is an incredibly difficult place to go on tour at the best of times but [particularly so] when you are going there with – and I think Geech [McGeechan, the head coach] alluded to the fact – maybe as many as six players that he might not have selected on that tour . . . I think we had that to overcome as well as the opposition in 93. The book is all about the learning from that – lessons good and bad. Geech learned very much from that and said I'm going to be responsible for picking my players from now on and he was able to do that for 1997 and for 2009.”

Despite ending up on the wrong side of history in that 93 series, when the Lions went into the final Test at Eden Park with a chance of emulating the 1971 tourists as only the second side to win a series in New Zealand, Hastings says he is not plagued by sleepless nights over it.

“You look back now, we kind of got robbed in the first Test which I talk about in the book. Is it a dull ache in my head? No. I don't wake up in the middle of the night and think 'I can't handle this'. Equally, it would have been fantastic had we gone down there and been another Lions team that managed to achieve success and only been the second team in history to win on New Zealand soil. It would have been nice to win another couple of Triple Crowns or Grand Slams with Scotland but that wasn't to be either. That's sport. In 93, the Saturday side was a very focused side, very committed and we gave the All Blacks a good run for their money.”

And what of this year's Lions and their captain, Alun Wyn Jones, who bounced back from a miserable 2020 to lead Wales to this year's Six Nations, can they give the world champions South Africa a similar run for their rand?

“It's an interesting squad and if they can gel I think they are capable of playing some great rugby. There is a lot of variety there, there is a lot of youth, there is a lot of experience. I think that this could be the most incredible part of Wyn Jones' career, notwithstanding everything that he has achieved. If he comes back having won two out of the three Test matches he is going to be up there with the Lions greats of that there is no doubt. All credit to him – as a former Lions captain I just wish him all the very best.”