Change to overtime, do I have any rights?

[StrongerThanIThought76]

Currently claim nearly £70 a month (gross) for a duty that I do at work. It is voluntary and you sign up each year for more or less (or zero) hours. There is a business need for employees to carry out this role and most people do take up the hours and claim accordingly.

There are changes happening in the new year to do with the structure of the working day that mean that myself and 2 colleagues are the only ones in the whole organisation who will not now be able to work this additional role due to us not being able to be certain about when we are available.
(It is not overtime that can be tagged onto the end of the day).

If we've been doing it for 4+ years and we are looking at a salary reduction of £800 per year, do we have any legal standing to argue that because the changes are out of our control we should continue to be paid until the hours are re-negotiated? What about next year when we could re-apply but cannot be accepted due to our working pattern?

Frankly that £70 A month has been the difference between food or gas bill for me over the last few years, I'm mortified that it's going to be taken away!

I'm waiting to hear back from my union.

Thanks in advance

I should have added - we have a contract for the additional duties which is re-issued annually after the negotiation period, at the very least they're in breach of this, surely?

We close tomorrow for the Christmas break so have only had one working day to get our heads round this.

If to the number of hours you will be working are going to be reduced, then your overtime pay will go down. If thr overtime isn't compulsory, then it is up to you whether you do it or not. If you chose not, then you won't get paid for it. If the contract is re-negotiated each year, then there's no contractual obligation on your employer either.

If you've had a fixed term contract (for the overtime - aka once you're signed up its then contractual for that year?) and you've had that fixed term contract for >2 years, I think you may have some rights.

But it's a bit of a grey area to me: I'm not an employment lawyer but I'm usually fairly well informed on these things. I think it will depend on the wording of the contract. If they were making you ineligible for it, they may essentially be making you redundant from that separate fixed term role? But then doing that if the role still exists would be very difficult. Sorry, that's a bit of a brain splurge but maybe gives some further points to discuss with the Union.

I think you're going to need to push the Union hard on this, given the consequences are so grave for you. I'd also consider getting in touch with ACAS and/or the CAB.