Before registering as a data controller a foster carer will need to address two main issues. The first is whether they are allowed to retain their own fostering records. The answer to this will depend on whether they are a self-employed foster carer or a worker/employee of their fostering service. Workers/employees have employment rights such as a statutory minimum level of paid holiday. The vast majority of foster carers do not enjoy these rights and so are self-employed with respect to employment legislation and so have every right to protect themselves by registering as data controllers.
The second issue they’ll need to address is whether they should register as a data controller. The answer to this will depend on whether they want to retain fostering records for their own purposes. If they want to retain records to protect themselves in the event of an allegation then yes, they will need to register as a data controller; if on the other hand they are happy to rely on their fostering service to protect them in the event of an allegation then no, they do not need to register as a data controller.
If you are satisfied that you need to register then the next step is to actually register with the Information Commissioner’s Office. You can do this at https://ico.org.uk/for-organisations/data-protection-fee/register/
This is a very brief overview of how and why you should register as a data controller – if you’d like a much more in depth look at this issue please read our article Foster Carers and the GDPR.