Originally with reference to the fact that if one owed a penny, one might as well owe a pound (pound sterling, UK currency) as the penalties for non-payment were virtually identical in severity.
Proverb
in for a penny, in for a pound
Having started something, one must see it through to its end, rather than stopping short; one must “go the whole hog”.
1964, Sanki Ichikawa, The Kenkyusha Dictionary of Current English Idioms, page 509: …in for a penny, in for a pound: if one undertakes something, it must be carried through at whatever cost.
in for a penny, in for a pound
Etymology
Originally with reference to the fact that if one owed a penny, one might as well owe a pound (pound sterling, UK currency) as the penalties for non-payment were virtually identical in severity.
Proverb
in for a penny, in for a pound
Having started something, one must see it through to its end, rather than stopping short; one must “go the whole hog”.
1964, Sanki Ichikawa, The Kenkyusha Dictionary of Current English Idioms, page 509: …in for a penny, in for a pound: if one undertakes something, it must be carried through at whatever cost.idiom. British. used to say that a person should finish what he or she has started to do even though it may be difficult or expensive.
"If you want to quit, I'll understand." "No, I'm sure we can do this. In for a penny, in for a pound."