Civil service/intelligence - how far do they actually go with clearance?

[Angelasparty]

Just curious really…obviously people working at the agencies are interviewed extensively to make sure they are the right ‘fit’. Of course references/background checks are highly in-depth, but do they remotely investigate other stuff too - eg internet use/tax returns/bank accounts/medical records etc?

I’m just wondering how far this actually goes? Surely it’s a GDPR nightmare if they are accessing confidential documents without people knowing?!

No it would work against them as long as all that information was given honestly. If your circumstances change in the duration of your clearance, you have to declare it e.g. A large inheritance, a big win on premium bonds, a new spouse or housemate etc.
Strangely, you don't have to declare children, despite the financial impact that comes with them.

As for travel to other countries, again you would be expected to declare it and undergo in house briefings, training etc. They would question your motive for travelling to a country on the restricted list for pleasure, and you could lose your clearance if anything nefarious was suspected.
Once you have this clearance, you are expected to exercise common sense (so don't book a holiday to North Korea), don't shout about it, maintain it. It costs a lot to vet someone so private companies are often on the look out for people who already have it and can be keen to recruit (looking at you Northrop Grumman).

Yes there are questions about sexuality and sexual practice (porn use etc), again honesty is the best policy. They don't care if you're into something freaky as long as you're not leading a secret double life.

It's intrusive but given the level of information those that have can be party to, that's a good thing I think.