If your medical condition is classed as a disability, you are afforded protection under the Equality Act (see separate FAQ). Certain serious illnesses such as cancer are automatically classed as disabilities under the Act.
Performance management measures are the first stage in the unsatisfactory performance process (UPP), which can ultimately result in an employee losing their job. The answer to the question “Can I be dismissed due to having a disability?” is a firm “No” – your Force should make efforts to find you a role to which you are suited, although if you are unable to work at all, you may be put forward for medical retirement.
Of course, there are many other conditions which are not disabilities but can still result in time having to be taken off work, and the question of being subject to UPP due to sickness is something of a ‘grey area’ which has featured in many employment tribunals. You should be referred to Occupational Health to discuss how your condition affects you, and your line managers will be given advice and recommendations on your condition and the roles you can undertake. We recommend you discuss the details of your case with your Federation or union rep – both bodies have extensive experience of dealing with sickness-related UPP.