Upvote:11
Have you given a list with all countries you have been to? If so, yes.
If you have not they cannot know all countries. Many people do not even know for sure themselves and there is no worldwide register for who visited where.
As indicated in a comment, the UK may have more information than you have provided them with, from countries they exchange information with or from searching your personal history if they suspect you of serious issues. This is rare but better be honest when you give your list of countries.
Upvote:26
Unfortunately, this question smells like XY problem. Someone asking that is likely preparing for an immigration fraud.
While it's impossible to say for sure what the UK authorities know and what they don't, here's what happens in practice:
Those are people whose only job is literally finding out the truth and verifying every possible document, statement, database and piece of information they have access to. They've seen it all. If you've had problems in the past and somebody promised you help in getting a UK visa in exchange for payment, it's unlikely that they're going to come up with anything innovative enough to deceive UK Immigration. It's just going to hurt you in the long term, possibly for life.