Can my employer demote me instead of dismissing me?

Only if your contract or disciplinary policy allows demotion as a sanction, and a fair procedure is followed. Otherwise it is a change of terms that needs your agreement.

Can my pay be reduced with the demotion?

Not without your agreement or a clear contractual right. An imposed reduction can be an unlawful deduction from wages, which is claimed separately from any dismissal claim.

What if I am demoted after a secondment ends?

Your substantive role and terms should continue. Ask in writing for confirmation of the role you are returning to and raise a grievance if it is lower graded.

Should I resign if I am demoted unfairly?

Take advice before resigning. Constructive dismissal requires a fundamental breach and a prompt response, and resigning early can weaken other options such as a grievance or a settlement discussion.

Can I be demoted without a fair process?

A demotion reduces your role, responsibilities or pay and normally needs your agreement. A demotion imposed as a sanction requires a fair procedure and an appeal.