Wow, are photos that common in the UK? I've never done that, nor seen it, but then I've not been on the labour force that long (~5 years).
Basically all you would need to steal a person's identity.
Marital status and driving license status is common; NI number not so much (but it's not as valuable as a SSN). Citizenship is definitely important; employers are on the hook to ensure the right to work.