Every F1park constable in addition to any powers and immunities specially conferred on him by this Act, shall, within the limits of the park of which he is F1park constable, have all such powers, privileges, and immunities, and be liable to all such duties and responsibilities, as any police constable has within the F2police area in which such park is situated; and any person so appointed a F1park constable as aforesaid shall obey such lawful commands as he may from time to time receive from F3the Secretary of State in respect of his conduct in the execution of his office.