Immigration Act 1971

7 If, on a person's examination by an immigration officer under paragraph 2 above, the immigration officer—

(a) determines that he may be given leave to enter the United Kingdom; but

(b) is of opinion, on the advice of a medical inspector or, where no medical inspector is available, on that of any other fully qualified medical practitioner, that a further medical test or examination may be required in the interests of public health;

then the immigration officer, on giving that person leave to enter the United Kingdom, may by notice in writing require him to report his arrival to such medical officer of health as may be specified in the notice and thereafter to attend at such place and time, and submit to such test or examination (if any), as that medical officer of health may require.