The arrest and detention of all individuals suspected of committing an offence is an operational matter for the chief officer of each force area. However, all detainees must be treated appropriately and in accordance with Police and Criminal Evidence Act 1984 (PACE) Codes of Practice C&H (detention and detention in terrorism cases, respectively).
In particular, section 9 of PACE Code C sets out detailed requirements concerning health care of all detainees. Amongst other things, the Code requires the custody officer to ensure that detainees receive appropriate clinical attention as soon as reasonably practicable if, for example, the person appears to be suffering from physical illness, or appears to need clinical attention. This applies even if the detainee makes no request for clinical attention and whether or not they have already received clinical attention elsewhere. If the need for attention appears urgent, the nearest available healthcare professional or an ambulance must be called immediately.
The Government does not hold information on the number of individuals with a Parkinson’s diagnosis that have been detained in police custody.