I really don't understand.
I went from Lisbon to Birmingham with my backpack as my hand luggage, and everything was OK with that.
On the way back, I was forced to dispatch my backpack because it wouldn't fit the allowed size for hand luggage.
It was the same backpack.
Sure, I had two more t-shirts there, but I also had more clothes on me, and thus the backpack was even lighter.
And what do I see on the way back?
Other passengers with hand luggage way bigger than my backpack.
The result of it all?
Once I got to Lisbon, instead of simply walking out the airport, I had to stare at luggage for over 50 minutes until my backpack came out.