A BPSS (Baseline Personnel Security Standard) check in the UK doesn't have a fixed expiry date. It remains valid as long as the individual is employed by the same organization that requested the check or if they return to that organization within a year of leaving. However, employers may choose to periodically review certain elements of the BPSS, especially for non-UK citizens due to right-to-work legislation.

Here's a more detailed explanation:

No Expiry for UK Citizens:
For British citizens, a BPSS check doesn't expire as long as they remain employed by the same organization.

Re-checks Required for Changes:
If an individual changes employers, the new employer will likely need to conduct their own BPSS check.

Right to Work Checks:
For non-UK citizens, employers must re-check their right to work in the UK periodically, which is a component of the BPSS, even if the individual remains employed by the same company.

Periodic Reviews:
While there's no formal expiry, organizations may choose to conduct periodic reviews of the BPSS, especially if there are changes in an individual's circumstances, such as a new conviction or a change in employment.

Transferability:
BPSS checks are not generally transferable between employers.

Continuous Validity:
If an individual leaves a role and returns within a year, the BPSS check can be considered valid.