Company want to change my start time

Just wondering if anyone has advice on this. I have been working in a factory for over 30 years. The company start time are officiall 8am -4.30pm. However i have been working from 7am -3.30 pm for approx 20 years now along with approx 40 more people. Now some of this 40 start at 6am -2.30pm. Now the company are trying to change all this and put everyone on the 8am start. The problem is that we have built our lives around our start times and cannot change. Some people will have to take on child minders etc. The official start time as per the company booklet is 8am. Surely i have some rights if i am doing this shift for the last 20 years. Any info would be greatly appreciated. Our union is not much help either as they say we have to go by the company booklet which states our terms and conditions of employment.

Have you a contract with the company that states you have a 7 a.m. start, If not and without the support of your union then you must go with your employers terms.

This might be one for expert advice.

No contract in writing. Just word of mouth that i was told 20 years ago that these were my hours from now on. Might just get a bit of legal advice on how i stand. I think that after 20 years doing a shift that i must have some rights.

Rather than possibly have to pay for legal advice try ringing www.employmentrights.ie and they may be able to help.

Your employer cannot change your terms and conditions without your agreement.
If you have been doing the same hours for 20 years there is a precedent set. I would be very surprised if your current hours were not de facto your contracted hours.
If there is a good reason why they want to make the change can you not work something out as a group that suits all concerned?