For retail and betting shop workers (including workers at race tracks) there are special rules allowing many workers to opt out of Sunday working. But for workers in other sectors, whether or not you can be made to work on Sundays depends on what it says in your contract of employment.
In practice, in a 24/7 world, it is becoming increasingly difficult for Christian workers to keep Sunday special.
All employees with 26 weeks’ service are now entitled to make a request to work flexibly, and this could include a request not to work on Sundays. However, this is a right to request – not to insist.
Your request can only be refused for business reasons. These will depend on the needs of your particular employer but they might include, for example, staffing levels, demands for service continuity, the needs of other staff who will want to take weekend breaks and holidays, the cost of replacing you on Sundays and so on. It is a good idea to set out a list of the pros and cons to help you build your case and to think about compromises that would be acceptable to you.
Many employers are likely to want to be sympathetic to requests to avoid Sunday working where this is a practical option, especially as your employer is likely to be keen to avoid any possible religious discrimination.