Consultation comes first
Your employer must warn you that redundancy is a possibility and consult with you meaningfully before a decision is made. If the first you heard of it was the decision itself, that is a problem for them, not you.
Selection must be fair
If several people do similar roles, the criteria used to choose between them have to be objective and applied consistently. Ask to see them.
Notice and pay
You are entitled to your contractual notice, or the statutory minimum if that is higher, plus statutory redundancy pay after two years of service. Settlement agreements often offer more, in exchange for waiving claims, and you must take independent legal advice before signing one. Your employer usually pays for that advice.
This article is general information, not legal advice. For advice about your own situation, book a consultation.