16. An official of a foreign Government. required to travel to the United Kingdom to undertake essential border security duties, or a contractor directly supporting these essential border security duties where—N.I.
(a)they are in possession of a written notice signed by a senior member of their foreign Government confirming that they are required to undertake essential border security duties in the United Kingdom within the period during which they would, but for this exemption, have had to isolate in accordance with Part 2, and that that work cannot be undertaken whilst the person is complying with Part 2, or
(b)their deployment is in line with a standing bilateral or multilateral agreement with Her Majesty's Government on the operation of the Border controls within the United Kingdom.