Employment Contract ‘on-call’ question

[evancourt]

Hello,
my company was acquired by a larger organization in 2022, and I was transferred under TUPE regulations. At that time, the terms and conditions of my employment did not specify any requirements for out-of-hours support or on-call duties, nor did they mention any compensation arrangements for such situations. The only information provided regarding working hours in the terms and conditions I signed is as follows:
"transferring employees will move to <new employer>’s full-time working week of X hours per week but may be required to work hours/days in addition to the above as per requirements of their role.”
Recently, a senior manager from the US branch of the organization issued a directive requiring us to provide personal contact details for potential out-of-hours paging. Under UK employment law, would this request be covered by the existing clause in my contract, or is an explicit agreement needed between me and my employer regarding on-call hours outside of the standard weekly hours?

My understanding of the current clause is that it pertains to overtime or peak periods of work, rather than implying a continuous on-call obligation 24/7 indefinitely.
Hope that some one can give me some advice. Thanks in advance

[ULA]

All you have detailed is potential out of hours on call. However is this being done on a rota system? What arrangements are being put in place if you are called out in the evening and you have done your normal day hours in terms of rest breaks for returning to work the next day?

You also mentioned terms and conditions you signed? Where these with the old company or did you sign new terms on transferring, for which you agreed to changes in terms as part of the transfer?

You will need to provide more detail before I can advise further.