Minister of Magic from 1962-1968. Leach was the first Muggle-born Minister for Magic, whose appointment caused a number of traditionalists to resign their government posts in protest (JKR, Pm).
leach=To empty; drain. Synonymous with 'ooze.'
Mentioned in the third W.O.M.B.A.T. test posted on jkrowling.com (JKR).