imposition of any restrictions or requirements under regulation 5, impose on P a requirement to be  detained until the later of—  (2) Condition A is that—  (3) Condition B is that P—  (4) Where a special restriction or requirement is imposed under this regulation, the person  imposing the restriction or requirement must express it to be contingent on the incidence or  transmission of Coronavirus constituting a serious and imminent threat to public health as referred  to in regulation 3.  5. —(1) Where Condition A or B (set out in regulation 4) is met in relation to a person (“P”), the  Secretary of State or a registered public health consultant may—  (2) A decision to impose a restriction or requirement under paragraph (1) may only be taken if  the Secretary of State or, as the case may be, registered public health consultant considers, when  taking the decision, that the restriction or requirement is proportionate to what is sought to be  achieved by imposing it.  (3) A restriction or requirement imposed under paragraph (1)—  (4) Where a restriction or requirement under paragraph (1)(c) is imposed on or in relation to a  child, a person who is a responsible adult in relation to the child must secure that the child  complies with the restriction or requirement, insofar as that person is reasonably able to do so.  ( a )  See  sections 45C and 45T of the 1984 Act for the meaning of “special restriction or requirement”. This is a restriction or  requirement which can be imposed by a justice of the peace by virtue of section 45G(2), 45H(2) or 45I(2) of the 1984 Act.  Section 45G(2) includes references to detention and isolation.  3 (a) the end of the period of 48 hours beginning with the time from which P’s detention under  this regulation begins;  (b) such time as any screening requirements imposed on or in relation to P under regulation  5(1) have been complied with and the assessment referred to in that regulation carried out  in relation to P.  (a) the Secretary of State or a registered public health consultant has reasonable grounds to  believe that P is, or may be, infected or contaminated with Coronavirus; and  (b) the Secretary of State or a registered public health consultant considers that there is a risk  that P might infect or contaminate others.  (a) has arrived in England on an aircraft, ship or train from outside the United Kingdom,  whether directly or via Northern Ireland, Scotland or Wales; and  (b) has left, or the Secretary of State or a registered public health consultant has reasonable  grounds to believe P has left, an infected area within the 14 day period immediately  preceding the date of P’s arrival in England.  (a) (orally or in writing) impose on or in relation to P one or more screening requirements to  inform an assessment, by the Secretary of State or a registered public health consultant, of  whether P presents or could present a risk of infecting or contaminating others;  (b) carry out such an assessment in relation to P; and  (c) following such an assessment, (orally or in writing) impose on or in relation to P any  other restriction or requirement which the Secretary of State or, as the case may be, a  registered public health consultant considers necessary for the purposes of removing or  reducing the risk referred to in sub-paragraph (a), including a special restriction or  requirement( a ).  (a) by the Secretary of State may be varied (orally or in writing) by the Secretary of State;  (b) by a registered public health consultant may be varied (orally or in writing) by the  Secretary of State or a registered public health consultant.  Imposition of restrictions and requirements 