17Sheriffs and judges
(1)By reason of holding judicial office, a person is eligible to act as a member of the First-tier Tribunal if the person is a sheriff (including a part-time sheriff).
(2)By reason of holding judicial office, a person is eligible to act as a member of the Upper Tribunal if the person is—
(a)apart from the Lord President and the President of Tribunals, a judge of the Court of Session (including a temporary judge),
(b)the Chairman of the Scottish Land Court, or
(c)a sheriff (except a part-time sheriff).
(3)A sheriff may act as a member of—
(a)the First-tier Tribunal, or
(b)the Upper Tribunal,
only if authorised to do so by the President of Tribunals.
(4)A judge of the Court of Session or the Chairman of the Scottish Land Court may act as a member of the Upper Tribunal only if authorised to do so by the President of Tribunals (but see next instead for the Lord President and the President of Tribunals).
(5)By reason of holding office within the Scottish Tribunals, each of the Lord President and the President of Tribunals is a member of the Upper Tribunal and needs no further authorisation to act as such.
(6)An authorisation for the purpose of subsection (3)(a) or (b) or (4)—
(a)requires—
(i)the Lord President’s approval (including as to the person to be authorised), and
(ii)the agreement of the person concerned,
(b)in the case of a sheriff (apart from a sheriff principal), also requires the concurrence of the relevant sheriff principal.
(7)An authorisation for the purpose of subsection (3)(a) or (b) or (4) remains in effect until such time as the President of Tribunals may determine (with the same approval, agreement and concurrence as is referred to in subsection (6)).