Under developed or over proved I'd say... Possibly too wet if you were following an American recipe as their flour tends to hold more water.
The big bubble is caused by the lack of gluten structure allowing bubbles to merge. You can see the bubbles you have got are all quite tall, the bubbles have expanded upwards rather than evenly.
If you can figure out what went wrong then "bad" breads are more valuable than the good ones I think, as you can learn and refine your technique. They still taste good too!
Under developed or over proved I'd say... Possibly too wet if you were following an American recipe as their flour tends to hold more water.
The big bubble is caused by the lack of gluten structure allowing bubbles to merge. You can see the bubbles you have got are all quite tall, the bubbles have expanded upwards rather than evenly.
If you can figure out what went wrong then "bad" breads are more valuable than the good ones I think, as you can learn and refine your technique. They still taste good too!