It varies from category to category, of course, sir.
With regard to parents and grandparents, for example, local staff in the local office have a great deal of experience with the types of fraud that tend to be used.
When we have children in the upper end of the eligibility range and there's a very large gap in ages between siblings, or when we have children who seem to have remained in school long past the normal best-before date, we will, for example, verify those documents. In some situations, we'll even require DNA tests. We use things like that.