Brian Smith: Dublin and Cardiff will be tough, but home ties make England favourites

During my days in the England coaching team, one thing about the Six Nations was clear: if we were blessed with the luxury of three games at Twickenham, rather than lumbered with three on the road, we were serious title contenders. When we won the championship in 2011, the Italians, the French and the Scots all came to London – and lost. Those victories were the foundation of our success and I have no doubt that ground advantage was a significant factor.

The schedule for this year's competition is once again in England's favour. Not only are they hosting the same three teams, but they are alone among the big players – France, Ireland and Wales being the others – in having the hometown balance tilted towards them. (I should make clear at this point that I mean no disrespect to the Scots or the Italians when I say that no one seriously expects them to end up as champions. Do they themselves expect to finish top of the pile? I doubt it).

To my mind, England start as tournament favourites. The trips to Dublin and Cardiff are sure to be tricky – particularly the first of them. My Australian countryman Les Kiss, a quality defence coach who has been working in the Ireland set-up for a few years now, once said to me before a game: "Smithy, when these guys play England, they grow another leg. There's no winding-up to be done."

When the two countries meet over there a week tomorrow, it will be a genuine test of England's character. If we laid a ghost or two by winning in Dublin during the build-up to the last World Cup, quite a few of the current squad played in that city when it was a fully functioning graveyard for anyone in a white shirt and will not have forgotten the horror of it. There again, England can probably drop a game in a tight tournament and still win the prize.

Talking of the deeply competitive nature of the Six Nations, do we really need to introduce a bonus-point system? There has been a fair bit of discussion about the possibility but, in common with one or two of the current head coaches, I take the old-school view. Plenty of people have pointed out the obvious iniquity of a team winning all five games and missing out on the title because they scored too few tries – or, similarly, a side losing all five but avoiding the wooden spoon because none of their defeats was particularly heavy. I'd like to put forward a more basic argument in favour of the status quo: namely, that if a team wins more matches than anyone else, it's an affront to natural justice if it doesn't win the competition too.

Come to think of it, I also see the bonus-point mechanism in the Premiership as a cop-out. How is it right that some teams finish below others in the table, despite finishing a campaign with more victories? If I'm being frank, I don't really understand why we went down this road in the first place. I may be an Aussie, but it doesn't mean I believe the southern hemisphere has a monopoly on being correct.

Looking at the England selection for today's game, I love the decision to give Billy Twelvetrees a first cap at inside centre. It's a brave call, but a good one. The way I see it, Twelvetrees has everything you want in a No 12: he's big enough to work his way down the channel, he's skilful enough with his passing to bring the outside backs into play at the right times and he has a big kicking game. When I was with England, we were itching to get our hands on him and pleaded with Leicester to give him game time. Unfortunately for us, the Leicester guys wanted something different from their No 12 and played it their way.

I suppose one of the consequences of the move to include Twelvetrees was disappointment for Jonathan Joseph, one of my players at London Irish. The England coaches have mentioned more than once that we've been playing JJ in the back three rather than at outside centre, where he's won his caps to date, and it may have counted against him. But if you look at the great modern No 13s – Tana Umaga of New Zealand, Brian O'Driscoll of Ireland – they've been mighty figures in defence as well as being good distributors and dangerous runners. At this point, JJ is not as big or strong as he'll be when his physical development is complete.

In my opinion, the defensive role of the No 13 has changed over the last decade and now demands real physical presence at the breakdown. Ten years ago, JJ would have been the best No 13 in England, hands down. Probably the best in Europe. But the way the sport is played now, players who are brilliant in space, like JJ, need to be in the back three. It won't be long before he proves the point for me.

Today's winners? If the game was being played in Edinburgh, I wouldn't be too sure: I always found going to Murrayfield to be a real pain. But at Twickenham, I back England, especially if by performing well at the set piece they get on top early and break the Scottish spirit. There again, it could be a right old dogfight. That's the Six Nations for you.

Brian Smith is rugby director at London Irish and the former England attack coach. His fee for this article has been donated to Great Ormond Street Hospital