Application form.. can they ask these questions?

[alltoomuchrightnow]

I thought these days these weren't meant to be asked.. am filling in an application form right now (England)
Need age and date of birth, sex, nationality, marital status.
How is marital status relevant?

the question does have relevance once employed, as payroll systems will have a field for that in case people are wanting to share tax allowance with a partner, for example.

Yes, but that can be in all the new starter forms, because it's not relevant till then.

They can ask whatever they like.
Not so, asking if you plan to start a family for example, would be inappropriate, and 'they' really can't do whatever they want!

the question does have relevance once employed, as payroll systems will have a field for that in case people are wanting to share tax allowance with a partner, for example
Yes, and they'll clearly need each employees bank details too, but they haven't asked for that on the application form, have they, so that is unlikely to be the reason. You can't just collect all sorts of personal information on someone who may only ever have one interview with your company, you get the information you need once you decide idea to employ them!

”flowery :
Obviously your common sense is not common at all. No, my common sense is very common as it is applicable to all sensible people I know.
But go ahead and think that HR really is going to be interested in someone who willfully leaves off answering a question. It rather depends what the question is. Having worked in HR for nearly 20 years I have enough experience to identify that if someone leaves off a completely irrelevant question like marital status, it would not make good business sense to write off their application.
Have you thought that the question may be there for a reason? Nope. Can’t think of any good reason for including that question. You know, what with it being 2018 rather than 1918. I would be utterly embarrassed if a client of ours used an application form so ridiculously outdated as to include marital status as a question and I can’t actually think of a justifiable reason for including it.

Have you thought that the question may be there for a reason?
I think that is what the thread is about, isn't it! You seem to be implying that we should all just accept that the people at this company have a good reason for asking about whether we're married, and it's too hard for use to be able to understand what that could be. None of the reasons offered so far justify collecting that information prior to interview at all, and suggest a desire to pigeon hole people by their age, sex and marital status.
Incidentally, it's often not HR who wield all the power, the place where I work would certainly not leave decisions on people's suitability for interview to HR, and let them reject people based on them leaving blank boxes - they ask managers in the area where the successful applicant would work to select a shortlist.