Regulations may provide for circumstances in which a practitioner—
whom NHS England is investigating in order to see whether there are grounds for exercising its powers under section 151, 152 or 154,
whom NHS England has decided to remove from a list under section 151 or 152, or contingently remove under section 152, but who has not yet been removed or contingently removed, or
who has been suspended under section 154,
may not withdraw from a list in which he is included.