Related Rule
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 126. Visits to Persons Deprived of Their Liberty
The UK Military Manual (1958) provides:
Every internee must be allowed to receive visitors, especially near relatives, at regular intervals and as frequently as possible. When possible, internees must also be allowed to visit their homes in urgent cases, particularly in cases of death or serious illness of relatives. 
United Kingdom, The Law of War on Land being Part III of the Manual of Military Law, The War Office, HMSO, 1958, § 70.
The UK LOAC Manual (2004) states:
Every internee must be allowed to receive visitors, especially near relatives, at regular intervals and as frequently as possible. As far as possible, internees should also be allowed to visit their homes in cases of urgency, especially death or serious illness of relatives. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 9.71.
The United Kingdom’s Prison Rules (1999) states:
(1) Subject to paragraph (8), an unconvicted prisoner may send and receive as many letters and may receive as many visits as he wishes within such limits and subject to such conditions as the Secretary of State may direct, either generally or in a particular case.
(2) Subject to paragraphs (2A) and (8), a convicted prisoner shall be entitled –
(a) to send and to receive a letter on his reception into a prison and thereafter once a week; and
(b) to receive a visit twice in every period of four weeks, but only once in every such period if the Secretary of State so directs.
(2A) A prisoner serving a sentence of imprisonment to which an intermittent custody order relates shall be entitled to receive a visit only where the governor considers that desirable having regard to the extent to which he has been unable to meet with his friends and family in the periods during which he has been temporarily released on licence.
(3) The governor may allow a prisoner an additional letter or visit as a privilege under rule 8 or where necessary for his welfare or that of his family.
(4) The governor may allow a prisoner entitled to a visit to send and to receive a letter instead.
(5) The governor may defer the right of a prisoner to a visit until the expiration of any period of cellular confinement.
(6) The independent monitoring board may allow a prisoner an additional letter or visit in special circumstances, and may direct that a visit may extend beyond the normal duration.
(7) The Secretary of State may allow additional letters and visits in relation to any prisoner or class of prisoners.
(8) A prisoner shall not be entitled under this rule to receive a visit from:
(a) any person, whether or not a relative or friend, during any period of time that person is the subject of a prohibition imposed under rule 73; or
(b) any other person, other than a relative or friend, except with the leave of the Secretary of State.
(9) Any letter or visit under the succeeding provisions of these Rules shall not be counted as a letter or visit for the purposes of this rule. 
United Kingdom, Prison Rules, 1999 (consolidated January 2010), Section 35.