The shorter expression, “up to a point,” is a well-known idiom that is used to indicate that a statement is partly but not completely true; for example, “I understand his feelings up to a point.”

The English author Evelyn Waugh took this innocent phrase one stage further in his 1938 novel, “Scoop.” Waugh's book is partly a satire on the world of newspaper publishing; much of it is still true of newspapers today.

A central character in “Scoop” is a newspaper magnate in charge of the “Daily Beast.” This is Lord Copper, a tyrant who resembles many who head modern-day media empires. He is someone whose will is law, who must not be contradicted, and who is also surprisingly ignorant. His assistant, Mr Salter, has learned that even a simple “yes” or “no” can be tricky, as “Scoop” explains:

“Mr. Salter’s side of the conversation was limited to expressions of assent. When Lord Copper was right, he said, ‘Definitely, Lord Copper’; when he was wrong, ‘Up to a point.’

‘Let me see, what’s the name of the place I mean? Capital of Japan? Yokohama, isn’t it?’

‘Up to a point, Lord Copper.’

‘And Hong Kong belongs to us, doesn’t it?’

‘Definitely, Lord Copper.’”

And now ‘Up to a point, Lord Copper’ has entered the English language as – according to “Oxford Reference” -- an expression of polite or deferential disagreement. It is a clear “no.”

More Info: en.wikipedia.org