Whilst working on my cosworth the other day I noticed that the cambelt was on the front edge of the pulleys

On further investigation I noticed that it's rubbing against the side of the crank pulley and starting to fray the outside edge so I haven't started the engine since I noticed it

The other week we had the cambelt off to change the lifters so is it simply a case that the belt hasn't been put back on square or is there a problem somewhere?
Here's what it looks like now
I am planning on getting a new belt, tensioner fitted and getting the cambelt cover re-fitted because it was off when I bought the car.
Thanks.