Permanent contract to fixed term England

hello, please can I ask about employment contracts? I work for a local authority on a permanent contract. I

just passed my three year mark. 1 have applied for a

job within the same local authority but another team.

They are hiring both permanent and fixed term posts.

if they offer me a fixed term contract how would this

affect me? if they offer me a year that takes me over

4 years continuous service, would this mean they

have to keep me as permanent?