My bf currently works late shifts plus Saturdays one in every four weeks. He was informed yesterday that this will be changed to one in every 3 weeks. He believes his contract states he will work one in every four (he's digging out to confirm). If that is the case, is the company within it's rights to change the work pattern?
If his hours are laid out in his contract it will probably also include a statement about if the company need to change the working hours / place etc they will have to give a certain amount of notice. He will need to check his contract to find out for sure.