Fill gap between roof and wall

There is a thin gap between the wall and the roof of my garage which lets in some water when it rains. The roof of the garage is made of the old corrugated sheets. What is the best thing to fill the gap with? Is something like Unibond sealant appropriate?

Photos .....

How about foam fillers, like these...

http://www.wickes.co.uk/Wickes-Eaves-Fillers-For-Corrugated-Sheets-Pack-6/p/240165

Hi,
Here is a photo of the crack. Its not a very good photo. The gap is less than 1 inch at the widest point.

OK, makes sense, I think. Can you get photos showing the issue in context including some from the outside looking at the junction.

Thanks here is a couple more pics. Hope they help.

my garage of this type, at my old house, had wood vertically, then a horizontal piece that went above the corrugated material, covering that gap.

I replaced it while I lived there as it was rotten, and in the end I replaced in the same fashion. However this was because I couldn't undo without destroying, the hooks holding the roof down to the steel frame. If I had been able to do that, I would have spaced the sheets out a bit more (they were overlapped a lot in most places) and then created a situation where the vertical wood or board, could have been tucked under the first corrugation at each side, and do away for the need for a gap filler or horizontal piece.

If you have bit of time, a grinder and replacement hooks, or buy some extra roof sheet and extend the roof each side, this might be a better and more long lasting solution than trying to fill the gap.