"That was probably the hardest, most awful game they've ever played in their life. That's what they're thinking. They're thinking 'Oh my God, what has just happened?'"

An intercept try by Stuart McInally seven minutes previously is the only brief interlude to an England demolition job in which Eddie Jones' team scored four tries, a modest return for their superiority.

But in a scarcely believable second half, Scotland add five more unanswered tries to move to the brink of not just a stunning comeback but a first win at the home of their fiercest rivals since 1983, only for England to strike the cruel, yet familiar, blow in overtime to clinch a 38-38 draw.

Reid, who came on five minutes into the second half, sat down with BBC Scotland in 2020 to rewatch - for the first time - one of the greatest Calcutta Cup matches, and gives his insight from on the pitch and the changing room, including the argument that broke out between head coach Gregor Townsend and fly-half Finn Russell.

McInally stops tidal wave

After 29 minutes, England wing Jonny May gathers an audacious offload from Henry Slade, waltzes over the line, puts his hand in the air, and dives flamboyantly to score. The hosts have wrapped up a bonus-point before the opening half hour is over. They are showboating.

May has added to tries by Jack Nowell, Tom Curry and Joe Launchbury. But four minutes later, comes some hope for Scotland. "There he goes, interception," Reid says as he watches McInally charge down Owen Farrell's attempted cross-field kick just out Scotland's 22.

"I was off my chair [on the bench] at this point screaming probably louder than the whole stadium 'GO, GO, GO'. It was like one of those fat kids trying to run away from a dog or something, or seeing the ice cream van and running for it. The winger, Jonny May, one of the fastest wingers in the world couldn't catch him. Rambo has got some speed."

McInally remarkably holds off both May and Farrell to score under the posts. It's a rare moment of joy on the bench, but thoughts of a comeback are still remote. "We were sitting talking," Reid recalls. "We didn't believe. Nobody would expect us to come back and do what we did."

"We're going inside and we're going to get a bollocking," Reid says, watching the players traipsing off at half-time.

What happened inside the dressing room was thrown into sharp focus last year, after Russell was excluded from the Scotland squad after a breach of team protocol, amid a fractious relationship with Townsend.

"I'm sitting trying to convince Allan Dell to stay on because his knee's hurting. I'm trying to convince him to stay on for 70 minutes as I'm a 10-minute man, 20 minutes at a push," Reid laughs.

"On the other hand, you've got Finn and Gregor just kind of having a big domestic. It was more about tactics. I think we kicked a lot in the first half, it didn't really work and we needed to change it. Gregor wasn't really happy. You've got some people who say things just to be heard, for their voice to be recognised. But when Finn says something, he's saying it for a reason.

"You've got one guy who's out on the park getting eaten up and spat back out. Then you've got another who's just angry. These two guys come head-to-head. But after a while the anger settles down and they start a conversation, 'right how do we work together and get the team back up, or try not to get embarrassed out there'."

Reid recalls how calm Townsend was as he delivered his message to his troops - there was no hairdryer involved. "I expected him to come in and lose his mind," the prop says.

"I've had coaches flinging water bottles, flipping up tables. But he was so calm. He just came in and, instead of losing his head, he's saying, 'Let's wipe the slate clean and win this second half. Let's go out there and put the best performance you've ever put in in a Scotland jersey.'"

'A bit of hope'

Reid, now on the pitch, already notices a big shift in Scotland's intensity as they pour forward for the first of their second-half tries. Russell puts Sam Johnson through a gap and, after a series of offloads and some quick ball, Darcy Graham steps past two white shirts to score in the corner.

"You can see the speed at breakdown, that's like two seconds, one-and-a-half seconds," he says as he points to the replay of the score. "No team can cope with that when you get that fast ball. When you get that in the wee man's [Graham's] hands, he's exciting. He's a tiny boy but he sure punches above his weight. Darcy's try gave us that lift, that bit of belief, a bit of hope."

'We can win this'

The momentum is now slowly shifting. Magnus Bradbury gathers the kick off and blitzes through three tackles before eventually being hauled down. Scotland passes that hit the deck before the break are now going to hand, and there is a speed to their play and a sluggishness about England.

And, perhaps most importantly, the bounce of the ball seems to being going in Scotland's favour. Price attempts a chip over the top inside his own half, gathers and feeds the onrushing Bradbury from nowhere to charge under the posts.

Townsend watches on without even a hint of a smile. But on the pitch, something is stirring. "We can win this game. That was the belief," says Reid. "When you're down that much, nothing really matters anymore. You've got nothing to lose, and that's when you manage to find that extra bit of energy, that extra grit to get in there and do it."

'We're on the cusp of something special'

"The wee man again," Reid laughs as Graham races in at the right-hand corner for his second score, and Scotland's third in just 13 minutes as Twickenham is stunned.

Russell's prints are all over this try as he loops a ridiculous pass out to Sean Maitland, who feeds Graham for the finish. As Greig Laidlaw puts the conversion wide, England are huddled under the posts in frantic discussion, there is hysteria in the stands, but Scotland remain calm.

"It's just total focus," Reid explains. "We know we're on the cusp of doing something special but it's just a matter of 'we just need to keep going'. We know how good a team England are, we know they do come back so we need to keep our foot on the throat."

'It puts chills down your back'

Sitting in front of the screen, Reid watches on, engrossed in a contest he knows the outcome of. "You can definitely see it in England's defence and attack - they're slow to the breakdown, slow to get set."

Just moments later, the prop watches Russell race under the posts having picked off Farrell's pass. "It puts chills down your back," he says. "When you're watching it again, you're like... not many people have been involved in a game for Scotland, never mind one like this.

"You're just buzzing. It was the same at the World Cup [in 2015] when we played against Australia. Unluckily we lost that with the last kick of the game, but it was the exact same when Mark Bennett intercepts the ball, it just sends chills down your back."

'Can you blow the whistle now?'

Remarkably there is a period of 15 minutes without a try. But it's still frantic. Slade is just nudged into touch as he races down the wing, and Maitland has a rampaging run for Scotland. Laidlaw misses a penalty, but it's not a day for three points.

It's open, unstructured rugby, and up steps Russell again. He identifies Billy Vunipola defending in midfield, with space to his left. Russell carries towards the England number eight, who attempts to smash him, and without looking, the fly-half puts Johnson careering through the gap.

"You would never expect him to finish that," Reid says of the centre. "Even when you look at it, there's two English players back, you don't expect him to score."

But with the help of an almighty fend, Johnson does score, and Scotland lead with three minutes left.

"I'm tired, but there's just that emotion, like 'oh my God'. You're knackered but you're like 'come on!', and I'm talking to the ref saying 'can you blow the whistle now?'."

'Boys are absolutely blowing'

Having rocked England for 40 minutes, it's Scotland's turn for some pain as they are forced to close out the game. "You're defending like your life depends on it," Reid says. "Boys are absolutely blowing. It's finger-biting."

The prop sighs as Scotland hooker Fraser Brown is penalised at the ruck as the clock turns red, allowing England to kick to the corner. Phase after phase is repelled, but penalty advantage is awarded to England for another infringement. It's desperate stuff.

"They go wide here and the best thing they could do was score really, but look at the bodies on the line," Reid says as Jack Nowell is stopped inches short in the left-hand corner.

But back in-field they come, and George Ford shows and goes inside Johnson under the sticks, giving himself an easy conversion to tie the game at the death. A cruel blow.

'We should have won'

From down and out to on top of the world, to the sucker of conceding at the death, the Scottish players had been through just about every emotion it's possible to feel on a pitch.

Fans and pundits sang their praises for their comeback and the style of it, too. It was Scotland at their best, the like of which has not consistently materialised in the two years since. But in the bowels of Twickenham, there was deep disappointment.

"We had the president come in and all the committee people at the SRU and they're all rubbing your back, but deep inside you just want to tell them to get tae," Reid says. "It was an amazing game to watch and everybody who watched it said that - but we should have won."

Townsend's face at full-time told the story of his own frustration at not holding on, but he was philosophical with his players.

"He was gutted as much as anyone else but proud that we went out and won the second half," Reid recalls. "Obviously everyone was writing us off at half-time and saying this is going to be a disgrace, a 70-pointer, the biggest defeat in international rugby and all that rubbish.

"Not every team can come from 31-0 down to then scoring those great flair tries in the second half. We retained the Calcutta Cup which was great, but we should have won."