Proper sausage from the butchers, free range egg on homemade bread with a bit of brown sauce and white pepper. It just doesn't get any better than that.
I suppose if you are in the middle of the Atlantic and your yacht has capsized then a rescue boat or a lifejacket would come first before a sausage and egg.
Although, if the sausage and egg sarnie was in a sealable bag then it wouldn't get soggy, and would be a great last bit of scran before you sank to the deep blue depths of the Atlantic.
So to summerise, nothing beats a sausage and egg sarnie unless you are drowning in the Atlantic, then it becomes a the second best thing (unless it's in a sealable bag then nothing beats it).