I just woke up. He claimed to be from WSJ in London, phone number is indeed from London. Was for an enquete and I didn't know what to think so I decided to let him ask the questions and I'll see if I answer.
He already knew my last name and first letter, from company registration presumably. I told him my age, that I have no mortgage, that I don't own the house in which I live, that the influence of the interest rate on my savings was slightly negative and one more question, I forgot what it was but something that seemed just as useless for a fraud to know. Maybe do you work at home?

I also spelled my full first name and gave them my spam e-mail address.
I'm puzzled. Nothing seemed wrong to answer, otherwise I would've hung up but he sounded quite oriental.
Thoughts on whether that's legitimate and whether they can use any of this against me?

None of it was secret..