There is no such thing as a cast-iron certainty in football.

That is why even the most ultra-confident Norwich City supporter can afford to take nothing for granted when Scunthorpe United, 23rd in the Championship table and beaten in their last eight away matches, arrive at Carrow Road tomorrow.

On the face of it, it is the most obvious home banker of the day. The team second from top, beaten just twice in 24 matches, entertaining the team second from bottom – it doesn’t get much more one-sided than that, other than top against bottom, especially when one studies the visitors’ record on their travels since New Year’s Day.

Eight away games, eight defeats, one goal scored and 18 against – Scunthorpe have returned home empty-handed from successive trips to Doncaster, Leeds, Middlesbrough, Cardiff, Bristol City, Portsmouth, Barnsley and Ipswich.

And they have the leakiest defence in the division with 68 goals conceded in 38 games.

By contrast, the Canaries’ last eight home games have brought five wins and three draws. Barring an own goal and a fluffed penalty, that would have been seven wins and one draw.

And yet, and yet . . . there are still one or two slender straws for the small band of travelling Scunthorpe fans to clutch tomorrow as they take their seats in a small island of claret and blue in one corner of Carrow Road, surrounded by an expectant packed house.

One crumb of comfort could be City’s struggle on home territory to see off the Championship’s more lowly sides, illustrated by home draws against Doncaster and Preston in recent weeks and the defeat earlier in the season by Crystal Palace, their worst result of the campaign and the only away victory enjoyed so far by the Eagles in 19 attempts.

There was also the FA Cup home defeat by Leyton Orient, which caused no damage to City’s league progress but again proved that they are occasionally vulnerable on their own ground.

Even as they swept all before them in League One last season, the top against bottom clash on Easter Monday – a year ago this weekend – brought the Canaries only a narrow 2-1 win over Stockport.

One other factor that could work to Scunthorpe’s advantage is new manager syndrome. Though managers themselves are inclined to dismiss this phenomenon as nothing more than coincidence, it is remarkable how often a new face, with Alan Knill appointed Scunthorpe boss yesterday, can inspire the most unlikely of results. If all that fails to provide any comfort to the visiting fans, they may recall that the Iron did, somehow, win six away matches before the turn of the year. And their one last desperate thought is that surely, sooner or later, they must get a point on the road – and the last seven teams to visit Norwich in league and cup have all managed to score once.

Of course, logically, none of this should make a scrap of difference and City will be firm favourites to complete their fifth Championship double of the season.

In the current form table produced by the Football League, Scunthorpe are joined in the bottom three of the Championship by two more of City’s remaining home opponents, Coventry and Nottingham Forest, both of whom have gone seven matches without a win.

So from a cold analysis of the rest of the Canaries’ home programme, those four matches ought to yield more than enough points to confirm a play-off place – they may not even need to reach the estimated cut-off point of 75 – but it is how they fare on their travels that will determine whether the much bigger prize of automatic promotion can be secured.

City have a brilliant away points tally of 32, matched only by leaders Queens Park Rangers, who have an identical record on their travels of eight wins, eight draws and only three defeats.

Yet each of the Canaries’ remaining four away games is potentially as tough as old boots, for different reasons.

Watford are likely to still be harbouring play-off ambitions of their own when City visit Vicarage Road on Tuesday week, and they will be bidding to become the first team to double Norwich since Paul Lambert became manager.

Ipswich Town have little to play for in their remaining games, except the overriding need to make amends for their hammering at Carrow Road in November and throw a spanner in the works for their promotion-chasing neighbours. A very warm welcome is guaranteed, but not in the friendly sense.

And Portsmouth has become a fiendishly difficult place to go since Steve Cotterill took over as manager. They have not conceded a goal in their last five home games and have won four of them.

Before any of those encounters, however, comes arguably the biggest of City’s final eight games, at Swansea City on April 9.

The Swans, beaten 2-0 at Norwich back in August, have had probably less acclaim than any of the promotion contenders, but have quietly gone along accumulating points, almost unnoticed at times. Only QPR have won more games at home than Swansea, only QPR and Forest have lost fewer.

Five of City’s final eight fixtures have been switched from their original date or kick-off time and such is the disruption that twice they kick off after their rivals have played, and twice they play before the rest. The rest of the day’s results will be known by the time they kick off at the Liberty Stadium at 5.20pm a week tomorrow – a win there and supporters will truly believe it is meant to be.

City’s longest journey of the season could prove to be the most important of all.