Sean O'Brien crabs over the top of the ball, wrapping up Jonny Gray and forcing the turnover.

Paddy Jackson kicks down into the Scotland 22m.

Their line-out is safe and secure this time as well.

Image source, PA

Keith Wood
Former Ireland captain on BBC One

I'd look at the bench and think that Ireland has a stronger, more experienced bench. 

Also, if you look at results over the past year, Scotland have been at their weakest in the last 10-15 minutes so I think that may be where the game could change.

Flanker Hamish Watson takes the kick-off and Stuart Hogg boots long up towards halfway.

Ross Ford is still on at hooker for the hosts. That switch seems permanent.

The teams are back out. Deep breath. Here we go.

Rory Lawson
Former Scotland captain on BBC Radio 5 live sports extra

It is so easy to preview a Six Nations before a tackle has been made or a ball has been kicked.

I had belief in Scotland, but did not think we would be standing here watching a 21-8 half-time score. 

Normally you see the hordes go out before half-time to grab a pie or a beer, hardly anyone has budged. The anticipation for this second half is there.

Andy Nicol
Former Scotland international at Murrayfield

The challenge for Scotland is to try to maintain the intensity they have started with. 

Image source, Getty Images

Scotland have put their bodies on the line defensively with 92 tackles. Can they repeat the feat in the second half?

The Daily Telegraph

Image source, The Daily Telegraph

England are attempting to become only the sixth team in Six Nations history to put together back-to-back Grand Slams. The most recent were France in 1997 and 1998 and England in 1991 and 1992.

The Daily Telegraph's rugby union correspondent Mick Cleary is eloquent on the task facing Eddie Jones' men:

"The Grand Slam citadel is not readily breached and no opponent is an easy touch. It’s a tough gig," he writes. 

"England are perennial targets, external, the butt of Celtic disdain, and at no time more so than this year. The bull’s eye on their white shirts has grown ever larger, ever more inviting."

Kick-off at Twickenham is a little over an hour and half away.

Image source, .

Whatever twists and turns this season's Six Nations championships take, let BBC Sport be your guide with alerts direct to your phone. 

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No, not the high-octane Scotland v Ireland game...

Remember when astronaut Tim Peake broadcast from the ISS last year? Well, his French counterpart Thomas Pesquet has been giving it a bit of 'Allex Les Bleus' from space this time round: Click here to see his message., external

Ireland have made 166 metres to Scotland's 165 but trail 3-1 on tries scored.

Steve Trow: Can I change my vote for who will win, I don't think it's gonna be Ireland any longer...

Gareth Vaughan: Based on this first 35 minutes - the Lions squad will be well represented by Scottish players. I wonder what Warren Garland is making of this though? He said he already thought he knows 15-20 players in the squad before the Six Nations even started. One would presume that a significant proportion of these likely picks were Irish - but they're getting totally outplayed by their Scottish counterparts. 

Valleyboy: is this Scotland? Its Like watching Fiji in sevens rugby cutting Ireland to pieces 

Image source, Reuters

Jamie Heaslip was Ireland's top carrier in the first 40 with 11. However Scotland's defenders restricted him to just 11 metres gained.

Chris Paterson
Former Scotland international on BBC One

We've seen some brilliant tries and brilliant endeavour from this Scotland side. 

I'm just blown away by the intensity they have come out with. 

Gordon D'Arcy
Former Ireland international on BBC Radio 5 live sports extra

There has to be some tough questions asked of Ireland. They have to prevent Scotland playing in those wider channels.

From kick returns, Scotland are kicking it to Ireland 70 yards down field and saying 'we'll defend you from half way', while Ireland are looking to run it out or box kick it out.

Scotland flanker Hamish Watson has accumulated 16 tackles with no misses and six carries for 22 metres in the first half.

Rory Lawson
Former Scotland captain on BBC Radio 5 live sports extra

Scotland have been very patient, they have made their tackles. They have looked good in defence, but it is exhausting.

Scotland will look at that final attack as a missed opportunity, but to go in with three converted tries is fantastic stuff. Vern Cotter will be delighted.

I would say they deserve to go in in front.

Andy Nicol
Former Scotland international at Murrayfield

Unbelievable finish to the first half! What a first 40 minutes to this Six Nations.