- Basic disclosure
- Standard disclosure
- Enhanced disclosure
- Protecting Vulnerable Groups (PVG) Scheme
Depending on the level of disclosure, "spent" convictions may need to be disclosed. You can however apply for spent convictions to be removed from the disclosure process.
As an employee for a private consultancy which was carrying out software development work for the Scottish Government I had to get a Basic Disclosure to be able to perform my duties on that contract.
It's not that unusual for certain types of work.
[0]: https://www.mygov.scot/organisations/disclosure-scotland/
It asks but doesn't mean you're automatically denied. BUT a just pardoned person in Seattle would have to answer yes if Canada asked the same question (they probably do)