It might have become Scott Johnson's favourite word over the past few weeks, but consistency is one quality that is likely to be entirely absent from the Mississippi Mud Pie of a Murrayfield pitch when Scotland and England get down and dirty on Calcutta Cup business come Saturday afternoon.

This year's clash of international rugby's oldest and deadliest rivals promises a kind of slapstick not seen since the glory days of Tiswas and the routine dumping of messy substances over the head of Sally James. In which light, the SRU's announcement on Tuesday that the hallowed surface is to be torn up and replaced by a kind of hybrid weave - apparently, the technology was first tested on Austin Healey's scalp - had a whiff of that old rugby strategy of getting your retaliation in first.

At the time of writing, the weekend forecast is rather less apocalyptic than it was just a few days ago, but the indications are that it will still be just a bit wet in Edinburgh when the game kicks off at 5pm on Saturday. England coach Stuart Lancaster is not the sort of fellow to ignore that sort of thing - as his predecessor, Clive Woodward, famously did 14 years ago - but the question of whether the conditions, overhead and underfoot, favour his side or Johnson's will only be answered conclusively around 6.30pm that evening.

Yet if suggestions are to be believed then the introduction of the human truffle hound that is Chris Fusaro does indicate that Johnson believes the ground battle could be critical this weekend. If the former Howe of Fife flanker is indeed to win the debut cap that has been so frustratingly elusive until now, then his role will not be to wait politely in the wings, rather to thrust himself centre-stage at every opportunity.

Clearly, Scotland took a battering off Ireland in the breakdown battle last weekend. If there was an element of complacency from knowing that Sean O'Brien was not going to be on the pitch, they got the rudest wake-up call imaginable. The Irish back row of Peter O'Mahony, Chris Henry and Jamie Heaslip put in one of the great shifts, blasting Scotland off the ball at every opportunity. If it was there to be won, they won it.

England are not remotely in the same league in that particular department. But on the evidence of their narrow loss to France in Paris, they are still a side on the up, and one that is certainly gaining confidence. Their loose trio of Tom Wood, Chris Robshaw and Billy Vunipola crashed, banged and walloped their way through the game; the question now is whether they can exert the same influence in rather less favourable circumstances this weekend.

The likelihood is that the battle will be closer - in that area at least. Scotland should be better than they were in Dublin, and England much less impressive than Ireland. But as stark as Scotland's deficiencies were in the breakdown battle, that was far from being the only department in which they were found wanting. A set-piece that coughed up possession at critical moments was just as much a problem.

Goodness only knows what part Murrayfield's far-from-level playing field will play in that regard. Neither side is likely to enjoy their day at the scrummaging office, but the England pack will still have an advantage in raw power. If scrums start to drop and the referee - as referees do - gives the benefit of the doubt to England then Scotland could find themselves on a wicket as sticky in metaphorical terms as it is in the literal sense.

So much for winning the ball - or not. There was a powerful impression at the Aviva Stadium that Scotland were no more adept at using it than they were at getting it in the first place. Much of that came down to a level of predictability at half-back, where Greig Laidlaw, in particular, was all too easily policed by the Irish fringe defence.

Laidlaw has been criticised in some quarters for taking two or three steps before shipping the ball on. There is a kind of rationale to this, as it can keep the ruck defence tied in a critical second longer. In short, you have to keep the opposition guessing, but the guesswork went out of it for the Irish when it became clear that the Scottish scrum-half was not inclined to try the break inside.

Laidlaw, it seems, will keep his place on the strength of his kicking, and keep Chris Cusiter, much more of an all-rounder, on the bench. The Borderer is too good and too clever a player to believe he can adopt the same unvarying tactics against England. The lesson for him - and, indeed, right across the Scottish backline - is that more of a mix is required.

England certainly looked vulnerable when they had to turn and chase back against France. Of course, France wing Yoann Huget enjoyed such luck with the bouncing ball last Saturday that you would have been more tempted to ask him for his lottery numbers than a technical explanation at the finish, but there's no harm in planting a few seeds of panic with probing kicks anyway. It's not as if Scotland's endless churning and recycling - well, endless until the Irish breakaways brought a halt to the process - brought much dividend anyway.

The impression is that Scotland are not that far away from being a decent team. The challenge for them on Saturday is to prove it.