Bowell
Your hours of employement and shift patterns can be changed without your agreement, if your employers ask you to change your hours or shift patterns and you refuse then all they do is give you a 1 or 3 month written notice of changes in your contracted hours/shift patterns...
Your employer can effectively cut your pay as well, they can't change the hourly rate for you job, but what they can do is give you a 1or 3 month written notice of reduction in your hours, or do what my husband company done, give you a 1% pay increase (he hasn't had one for 2 years) extend the next pay review to 18 months, and stop paying Bank holidays at double time,as my husband work in the care sector, he's works every monday, as part of his rota... So his pay cut has been cancelled out completely and minused! And that was his first pay raise in 2 years!!!!
The other way of reducing pay, is recontact you into another position with lower pay!