Law queries
The local authority I work for has a system where whenever it fails to reach agreement with the union on any changes it wants, it just issues 12 weeks' notice and then imposes the change. How many times can they do this before the job they are asking you to do is no longer the job you originally signed up for? At what stage can you deem yourself unemployed or redundant?
Employers cannot lawfully change contracts simply by giving notice of the change. Any contract change requires agreement and an employer who goes ahead without getting agreement risks at the very least claims of breach of contract or even constructive dismissal from workers who have had enough and decide to leave.
You should be making it clear to your employer that unilateral changes are almost always unlawful and mean that workers can challenge them.
You should also point out that a legal ruling in 2000 makes it absolutely clear that employers must consult with representatives before making any changes to contracts. And the standard of consultation is similar to that required in redundancy cases.
* More information: GMB v Man Truck & Bus [2000] IRLR 636