Public street, you can take photos and smoke at the same time.
In shopping centres, you can only do what the landowners allow you to.
It's not a public place, but a publically accessible place, there's a difference.
While you are free to wander onto the land, there will be terms and conditions attached to that access. They don't have to publish those terms (by way of a sign etc), but can stipulate what you are or not allowed to do on that land.
If they say "No photography", then its no photography. The moment you start taking photos, you are breaching your conditions of being allowed on that land, and are committing trespass.
Trespass on its own is a civil offense, not a criminal one, so in the first instance, they must ask you to leave, nothing else. They can't make you delete shots, they can't take your camera off you, they can't even 'detain' you until the police arrive.
Once you then refuse to leave, it becomes a different matter IIRC (Although from this point I'm not sure how it's different).