Job schedule suddenly changed: ask the expert
I understand from your email that you accepted the position last October based on a Tuesday to Saturday working week. I am not, however, certain whether you were issued with a contract and whether the days on which you were supposed to work were stated in your contract. If so, then changing the days on which you work by text without consultation is likely to amount to a breach of contract unless there is a right reserved in the contract for the Company to amend the days on which you work on notice. You will need to check your contract carefully.
Even if there is the ability to change the days on notice, if the result of this is that you are impacted more than someone who does not have childcare responsibilities, you may be able to argue that their actions are discriminatory.
From a practical perspective, however, I am presuming that you would not like to immediately start alleging discrimination/breach of contract. I suggest that you raise the change as a formal grievance, making it clear that you took the job on the basis of the days agreed. Since it is also apparent that you cannot work either Sunday or Monday but do not want to be seen to be obstructive, I suggest that you say that you would be happy to work your original days, or if this is not possible to work, for the time being on Tuesday, Wednesday and Thursday. You should spell it out about how difficult it is for you to work Sundays and indeed Mondays for the time being.
If that does not work, then you could bring in the possibility of breach of contract/discrimination should you feel that you can no longer work at the organisation. You would not be able to claim unfair dismissal at the moment since you do not have a year's continuous service.
Laura Livingstone is an employment lawyer for Davenport Lyons in London. Her practice focuses on contentious and non-contentious employment work, but she leans towards the non-contentious. She has advised a wide variety of corporate clients in all areas of employment.