Erm, no. It has 3 net carbs, they have already subtracted out the fiber. Basicaly about the only completely carb free things are water and meat. They wouldn't have negative carbs, as the total number of fiber would be included in the total number of carbs, unless they have already subtracted the fiber. From what I understand the UK subtracts fiber most of the time. In the US some do and some don't.

Add up the calories of you are unsure. Basicaly take the fat grams and multiply them by 9, then take the protien grams and multiply them by 4. What ever you have left is the carb calories. So unless this bread has less calories then the number you get when you add up the fat and protien, there are carbs there.