Dictionary: Betty Martinhttp://www.worldwidewords.org/qa/qa-all3.htm
"Footnotes first. The phrase or saying, all my eye and Betty Martin means that something is total and complete nonsense
. It is found in British English
from the eighteenth century on, but is hardly known today
....Betty Martin was pretty obviously tacked on to the end of the existing all my eye
(in similar vein, Londoners later created all my eye and elbow, all my eye and grandmother, and all my eye and Tommy, among others, as well as shortening it to the exclamation my eye!, which remained common, especially in the US
, until comparatively recently"http://en.wiktionary.org/wiki/all_my_eye_and_...
"Phraseall my eye and Betty Martin
(dated) rubbish, humbug
1893 November, R.D. Blackmore, "Perlycross", in Macmillan's Magazine, vol. LXIX, page 83,
Oh, that's all my eye and Betty Martin! Nobody believes that, I should hope. "