Ireland win the penalty. It's central and just inside the 22.

Crowley points to the posts and this should be nailed on.

That's much more like it from Ireland! Jordan Larmour, James Lowe and Bundee Aki make some big ground and Ireland are roaring in tho the 22!

The Irish support are responding!

Off we go!

A HUGE 40 minutes ahead for both sides.

You wonder how much attention the English players are paying to this one as they gear up to take on France.

Remember, if Scotland come out on top here then it is all to play for later on.

How many twists and turns will there be over the rest of the day?

Colin Gregor
Former Glasgow Warriors back on BBC Radio Scotland

Finn Russell is sitting quite deep, and has been quite static.

I'd like to see him get flatter, but Scotland need quick ball for him to do that.

BBC Sounds

You can listen to the second half of today's game in Dublin on BBC Sounds, BBC Radio Ulster, Radio 5Live and Radio Scotland Extra.

Gavin Andrews is joined by former Ireland internationals Claire Small and Jonny Bell on Radio Ulster, and ex-Ireland flanker Chris Henry is on co-commentary alongside Jim Neilly.

Colin Gregor and Peter Wright are on duty for BBC Radio Scotland.

Former Ireland wing Tommy Bowe and Scotland hooker Fraser Brown are on Radio 5Live with Chris Jones.

A huge 40 minutes to come. You won't want to miss it.

Brian O'Driscoll
Former Lions captain on ITV

Scotland have been meeting Ireland and making trouble. Sometimes they're split or sometimes they've got 13 up front and two in the back just wanting to frustrate the life out of Ireland.

This isn't going to be a 15 point game. It's going to go down to the fine margins.

Scottish actor Gerard Butler is in Dublin, taking it all in.

It may not be Sparta, but it is awfully tense...

Image source, Inpho

Image source, Getty

Here's a reminder of all the permutations. With 40 minutes to play, your guess is as good as mine.

Ireland will retain the title if they win or draw against Scotland in Dublin.

If Ireland lose but secure a bonus point - for scoring four tries or finishing within seven points of Scotland - they will most likely clinch the title given their vastly superior points difference.

An Ireland defeat without a bonus point should still be enough if England win without a bonus point.

England will be crowned champions if they win with a bonus point and Ireland fail to collect a point. Scotland need to win with a bonus point, deny Ireland a point and overturn Ireland's huge points difference advantage to have any chance.

They then need France to beat England without a bonus point or with a bonus-point win by a smaller margin.

Here's a fun little stat from our friends at Opta.

Ireland have led at half-time in each of their last 13 men's Six Nations matches, the joint longest run by any side in the history of the Five/Six Nations, alongside England who led at the break in 13 consecutive games between 1998 and 2001.

Tommy Bowe
Former Ireland winger on BBC Radio 5 Live

Breathless, end-to-end stuff just before the break but overall a frustrating first half for Ireland.

Ireland walked off the pitch at the end of the first half there and they looked a bit deflated.

Gordon D'Arcy
Former Ireland international on ITV

It's going to take something special to unlock this Scotland defence.

That is strong defence from the Scots to end the half.

Ireland are 40 minutes away from the Six Nations title.

However, Scotland are right there and this is anyone's game.

Massive half of rugby ahead.

Image source, Getty Images

The clock is in the red but Ireland win the penalty in their own 22 as Blair Kinghorn, chasing his own kick, catches Calvin Nash around the head as the Irish winger stooped for the ball.

Time for one last attack?

Gordon D'Arcy
Former Ireland international on ITV

As this game goes on and the minutes tick by, you feel like Ireland are inviting Scotland into this game a little bit more.

Fraser Brown
Former Scotland hooker on BBC Radio 5 Live

Scotland have had a couple of chances but have coughed the ball up at key moments.

There is a bit of chaos with Scotland's attack which can actually work well but they need to be more clinical when they have the ball.

Colin Gregor
Former Glasgow Warriors back on BBC Radio Scotland

Ireland have been a little bit loose.

Their kicking game hasn't been where you'd expect it to be, little handling errors, and then Crowley misses his kick at goal.

It's now up to Scotland to take advantage.

It's just inside the Scottish half and he drags it well wide.

Still just the one point in it.

Another let off for Ireland and another error from Scotland. Zander Ferguson carried the ball forward but Andy Christie was in his way and stopped the Irish tacklers.

I said Christie had been everywhere. He was just too in the way there.

Jack Crowley points to the posts.

Scott Hastings
Former Scotland player on ITV

Andy Christie absolutely spot on. The patience and only committing one or two players to the break down makes the difference.

Christie and Jack Dempsey have been working in unison and it's a great duo to see.