post changed by restructuring

[doadvisemeplease]

I work in local govt and both manage and do most of the day to day work in my very small dept.
Recently I have had very strong reason to believe that they may hand over the managerial part of my job to a newly created strategic post. I won't get it as I am not prepared to work full time and also I know that someone is being groomed for it
If they keep me on my current role will almost certainly have to be re graded as a lot of my responsibility will be taken away
Do I actually have to accept a job with less money and less responsibility than I have been having for years? I think I might prefer to be made redundant - but I am worried that they will say I made myself redundant if I don't accept the alternative job.
Any advice or clarification on this would be welcome.

You wouldn't be entitled to redundancy if you refused to accept an offer of a "suitable alternative" job. A suitable alternative would be suitable for your skills and experience, and on no less favourable terms and conditions. If the job involves a pay cut or regrading, it would be unlikely to be a suitable alternative.

thanks flowery.
One important part that I missed out of my OP
my employers have a precedent for downgrading posts by tweaking the responsibilities. They then have continued to employ some of the same people - but they are on a reduced salary. I think it is protected for 2 or 3 years on a sliding down scale after which it reverts to the salary currently offered for the role.
I know that the people who have remained in employment on this basis have agreed to this. I am not clear whether they would have been held to make themselves redundant if they hadn't agreed?
Anyone know the legislation on this.
To me the terms and conditions would be less favourable if you ended up earning less - even if it took a while to kick in.