24) special cases where the Governor considers that the arrangement will be in the public interest. 87. Vacation leave may be extended by the Secre- tary of State on full or half salary at his discretion if the officer is required or permitted to remain in the United Kingdom by the Secretary of State on public grounds. 88. Sick leave on full salary may be granted by the Secretary of State at his discretion to an officer on the ground of ill-health for any period not exceeding six calendar months from the date of the expiration of his vacation leave; and where there is reason to believe that the officer will ultimately be fit to return to West Africa the Secretary of State may at his discretion extend such leave with half salary for a further period not exceeding six calendar months. If an officer who has been granted sick leave is found by the Consulting Physician to the Colonial Office to be fit to return to West Africa and fails to do so when ordered, he shall be liable to refund any pay which he may have drawn in respect of such leave. 89. Any extension of leave which may be granted on any grounds other than those mentioned in the two foregoing regulations will be without pay. 90. In addition to any leave which may be granted under the foregoing. regulations, an officer who has completed eight months’ residential service and is expected, subject to good health, to complete at least a further six months’ residential service, or who has been on the sick list and is reported by a Government Medical Officer to require a period of relaxation from duty to render him fit to complete a further six months’ residential service, may, at the discretion of the Governor, be granted leave to be spent in West Africa or on a sea voyage for purposes of relaxation from duty, up to an amount not exceeding 21 days in