Which demographic of English speakers say "I've to" for "I have to"?

In a forum I frequent there are many times that contractions are used in a way that's unusual, and many users find to be ungrammatical:

"I've to" etc.

To me it's not ungrammatical but it sounds both old-fashioned and like something you might hear in certain rural areas of England, but I don't know where.

Do some of our English experts here have more information on who uses or used this structure? Which region or regions and which age groups etc?

Solution 1:

Unfortunately I don't have any evidence past my own experience but I am 28 and I lived in the South of England until I was 18 and then moved to Scotland. I have heard "I've to" infrequently in England and never in Scotland. I would personally associate it with old fashioned but informal language.